This one is impossible to miss, it's the one where you are fighting dragons. Since enemies scale with your level there is no minimum level requred to be able to beat the game.
PROs: You kill dragons, like a lot of dragons, you kill Thalmor, like a few Thalmor agents
CONs: No big celebration in every city in Skyrim after you save the world.
Apart from the Dragon's threat, there is a civil war in Skyrim. You can either pick to join the Empire or the Stormcloacks, talk to many people, listen to their stories and make your own mind of who is in the right. Personally, ideally the Empire but in the weak and corrupt state the Empire is in, the Stormcloacks are the better choice, but I still picked the Empire in my playthrough.
PROs: Get rid of a weak and corrupt Empire that doesn't allow you independence.
CONs: Probably not as good as Hammerfell in beating the Thalmor.
This one is interesting because after the first missions you have the choice to join the Dawnguard or the Vampire Clan, I'm teling you this because I didn't realise I had a choice and just went with the vampires because I thought they would eat me if I refuse.
PROs: You get to become a vampire, a vampire hunter, or a vampire vampire hunter.
CONs: Both the vampires and Dawnguard have huge fortresses but mostly for the looks.
This one is cool, Dragonborn vs Dragonborn and you have a whole new island to explore. But this island is not part of Skyrim but of Morrowind as such you will find many dark elves there.
PROs: Get to see Morrowind, get to see the Skaal, more snow, powerful companion.
CONs: Get to see Hermaeus Mora, get to see Miraak, get to see that Telvani wizard.
What about Heartfire DLC? No storyline or quests, you just build 3 houses with that DLC, you can't even build a house in the best hold in the game, Winterhold, and the house from the 2nd best hold in the game, Dawnstar, is far away from Dawnstar in the middle of wilderness, I want to live with people! Winterhold has 4 destroyed houses that can be rebuilt, Morthal has one burned house and there are countless a abandoned house in Skyrim, but I guess they wanted to leave that to the modders. By the way, if you need a house the Hjerim house in Windhelm is the best, if you are okay with living in a place where a murderer used to live, but your character has probably done his fair share of killings too.

You can find them in Whiterun after you get the quest to send word to the Jarl, probably the first faction you will join, they have an interesting story with a twist. Through the storyline you will gain Eorlund Gray-Mane's legendary Skyforge Steel weapons, which are great at low level but pretty far from legendary.
PROs: You will have stories to tell.
CONs: People don't like stories about being a werewolf.
If you're more of a mage than a warrior you should try the College of Winterhold, just kidding, you can play any storyline regardless of what you play us. Nobody will find anything suspicious in a two-handed tank being a top student. So prepare for your Harry Potter's Hogwards experience in Skyrim.
PROs: You don't need to be a wizard to complete the entire college questline.
CONs: You don't need to be a wizard to complete the entire college questline.
You need to at least become a member of the thieves guild to complete the main quest with dragons, so you probably know this one.
PROs: Can join even if you're not a Khajiit.
CONs: No matter what you do, there will always be a Khajiit better than you.
A boy in Windhelm is trying to summon the Dark Brotherhood, you can't seem to mind your own business so bad stuff happen. This, the Dawnguard and the College of Winterhold were my favourite questlines.
PROs: You get a clown companion if you spare Cicero, then ask Lidia to follow you.
CONs: The Argonian assassin was supposed to be the best.
This one is short and I was expecting actually learning how to play an instrument in game or sing in real life, trust me, it's better to be dissapointed now than when playing the game.
PROs: You get to take part in a festival about how they hate a guy who is a hero in Sovngarde.
CONs: They don't teach you how to sing, you can't play instruments, but you graduated.
You become part of this faction as you advance in the main questline with the Dragons, but after you discover them you can do work within and for the Blades faction without touching the main quest so I guess it kind of counts as a separate dragonslayers faction. Just try to finish the Blades questline before finishing the main quest, trust me, you will thank me later.
PROs: They can kill dragons, this is why they mostly use swords.
CONs: Your boss is a narrow-minded fool, just like your real life boss.
This one is difficult to find because it's located in Windhelm's docks, which are also difficult to find until you get the Dragonborn DLC and realise that the city of Windhelm has docks. Don't lest this questline mislead you, the East Empire Company are a*holes too.
PROs: Expose the corrupt Shatter-Shield and help the corrupt East Empire Company.
CONs: So hidden, I didn't know about this one until I was over level 60.

Other factions in Skyrim that you can't join:
The Vigil of Stendarr -> These guys were cool and I wanted to join them, I went to their base and realised there are no quests there or ways to join the faction. After some more playing I realised they were rather weak, after the Dawnguard DLC the lore of the game confirmed they are rather weak, but they still look cool, "may Stendar have mercy on you for the Vigil has none to spare".
- Psijic Order -> Some mysterious super-advanced mages that help you on Winterhold College quests.
- Thalmor -> The real evil of this game after the dragons, the mission "missing in action" is so satisfying regardless of where you stand in the civil war because you get to kill Thalmor agents.
- Silver Hand -> When you play the Companions questline they are your main enemy.
- Penitus Oculatus -> When you play the Dark Brotherhood questline they are your main enemy.
- Greybeards -> They are your friends, but you aren't exactly a Greybeard yourself.
- Forsworn -> They won't accept you into their ranks and will try to kill you even if you are a Breton.
- Summerset Shadows -> Some joke wannabe thieves, a minor threat in the Thieves Guild quest.
- Morag Tong -> Morrowind assassins, hate you for being part of the Dark Brotherhood.

1. Azura: The Black Star -> You get a start that is able to absorb souls without breaking after use like a soul gem. Take the Black Stars as with that you can take human souls as well.

2. Boethiah: Boethiah's Calling -> You get a nice armor with some unique effects.

3. Clavicus Vile: A Daedra's Best Friend -> You get either a crappy Axe that looks better on stats but has a swing way slower thus making it worse than an average Axe, or Clavicus' Mask that will allow you to get better prices from merchants.

4. Hemaeus Mora: Discerning the Transmundane -> A book that gives you a lot of stats after you read it.

5. Hircine: I'll Met by Moonlight -> Either the possibilty to turn into a werewolf whenever you like or your own fur armor, I don't have to say where the fur comes from do I?

6. Malacath: The Cursed Tribe -> A powerful warhammer and a weak ork leader.

7. Mehrunes Dagon: Pieces of the Past -> A knife that can instantly kill the target if you're sneaky.

8. Mephala: The Whispering Door -> The more people you betray the stronger this sword gets.

9. Meridia: The Break Of Dawn -> Probably the only Daedra item that can be attributed as a force for good.

10. Molag Bal: The House Of Horrors -> A mace with some nice effects and the slow voice of Molag Bal.

11. Namira: The Taste Of Death -> Food, but not any type of food, you'll figure it out.

12. Nocturnal: Thieves' Guild Quests -> A key that opens all locks but that afterwards you will have to give up.

13. Peryite: The Only Cure -> A shield that protects you from both physical and magic attacks, pretty interesting gifts from one of the weakest Daedric Princes.

14. Sanguine: A Night To Remember -> Sanguine, my boy! A staff that can summon Daedra to fight for you, probably one of the most useful Daedric times, until you learn how to summon a Daedra by yourself.

15. Sheogorath: The Mind Of Madness -> A staff that creates a random effect, sometimes useless, sometimes funny, sometimes random.

16. Vaermina: Waking Nightmare -> I loved this mission, you either get the staff of Vermina or a powerful companion priest.

1. The Blessings of Nature -> In Whiterun's healing temple you work for Kynareth.
2. The Book of Love -> In Riften's temple of Mara you work for Mara.
3. The Heart of Dibella -> In Markarth's temple of Dibella you work for Dibella.
4. Kyne's Sacred Trials -> In the woods you work for Kyne which is baiscally Kynareth, I guess we know what's the Dragonborn's favourite divine.

1. The Forsworn Conspiracy -> Fighting crime in Markarth.
2. Blood on the Ice -> Fighting crime in Windhelm.
3. Laid to Rest -> Fight already made crime in Morthal, you can save the guy witched by Alma instead of killing him.
4. Promises to Keep -> A nice quest in Riften about a horse.
5. The Man Who Cried Wolf -> Go to Solitude's court and fight the feminist mages who try to summon the feminist icon Potema. #WeSummonPotema
6. Lights Out! -> A sneaky Solitude character gives you some sneaky work to do.
7. In My Time Of Need -> I love these quests, figure out who lies and that the Alkir warriors are telling the truth.
8. Missing in Action -> Talk to the Grey-Mane family, even if you're pro-imperial, the Grey-Mane deserve this, don't try the diplomatic method as it's bugged.
9. The White Phial -> In Winhelm go to the alchemist and help him achieve his life's dream.
10. The Final Descent -> In Raven Rocks, find out what happened in the mines, this is why I said the East Empire Compnay are a bunch of a*holes.
11. Served Cold -> Prevent an assassination attempt in Raven Rocks.
12. The Lover's Requital -> A murder quest in Riften's Jail.
13. Unfathomable Depths -> A quest about a Dwemer cave in Riften.
14. The Straw that Broke -> Help poor Narfi in Ivarstead.
15. Sanuarach Mine -> The only reason town Karthwasten exists is this quest.
16. Erik the Slayer -> Help this guy from Rorikstead become an adventurer.
17. Mine or Yours -> Minor quest in Shor's Stone.
18. Extracting an Argonian -> Rescue mission from Darkwater Crossing.
19. Dravynea's Frost Salt -> Bring some frost salts in Kynesgrove.
20. Dragon Research -> While in the Blades' faction, get that awesome potion from Esbern.
21. The Ghost of Old Hroldan -> An interesting small quest in Old Hroldan Inn.
22. Payment Delivery -> A small quest in Stonehills settlement.
23. Old Friends -> Help the a*hole mage Tel Mythrin from Telvanni tower.
24. Retaking Thirsk -> Help some coward Nords retake their home from some minions.
25. Gharol's Message -> Make a delivery in one of the orks' settlements.
26. Bromjunaar Sanctuary -> Not a quest but you can create the dragon priest mask Konahrik using 8 other dragon priest masks in Bromjunaar Sanctuary, and travel through time with the Wooden Mask.
27. No Stone Unturned -> You probably have 1 or 2 stones already so you know the quest, don't get your hopes high up, the reward is not that impressive.
28. Unearthed -> Help Ralis uncover an ancient Nord tomb in Soulstein, it will cost you a lot of gold.
29. The Ebony Warrior -> Once you reach level 80 a noob will ask you to duel him so he can get to Sovngarde, his defeat is so humiliating that he doesn't get to Sovngarde.
30. Lost to the Ages -> From Dawnguard DLC where you have to go inside an improved Dwemer city.
31. A Return To Your Roots -> Collect 30 Crimson Nirnroot from that abbandoned underground city.

1. Forbidden Legends -> Probably not that hard unless you don't like reading books in game.
2. The Pale Lady -> You need to be near Frostmere Crypt in Dawnstar domain to get it.
3. Frostflow Abyss -> Counts as miscellaneous quest but an interesting one about a crime.
4. Forgotten Names -> Under the College of Winterhold there's a mysterious hand, this quest is unmarked but a quest nonetheless.
5. Repentance -> Help Illia kill her evil mother in Darklight Tower south-west of Riften.
6. Coming of Age -> You need to be near Ironbind Barrow in Windhelm domain to get it.
7. Angi's Archery Training -> It's not a quest but you can find Angi's cabin south of Falkreath.
8. Liar's Retreat -> A cave south of Dragonbridge where a unique weapon called the Longhammer can be found.
9. Arcwind Point -> Not a quest but a difficult location in the game, south of Ivarstead.
10. Abandoned Prison -> Not a quest but an interesting location in the game, in the marsh between the Peak of the World, Windhelm and Riften.
11. The Chill -> Not a quest but an interesting location, get to jail in Winterhold or explore north of the College of Winterhold.
12. Karstaag -> In the north of Soulsteim you can find Castle Karstaag and fight a difficult boss.
13. The Frostmoon Hunters -> Asking in Raven Rock's tavern about rumors will point you to this.
14. The Affairs of Hagravens -> Help a friendly Hagraven from Blind Cliff Cave.
15. Kagrenzel -> Difficult Dwemer dungeon located north east of Riften in the mountains.
16. Siege on the Dragon Cult -> High level ghosts and a dragon priest south of Riften in Forelhost.
17. Kolskeggr Mine -> Talk to the miners from Left Hand Mine next to Markarth.
18. Return to Grace -> Greta, make sure you drop the amulet before talking to her to avoid an ugly bud.
19. Hemming's Sword -> Go to Hemming Black-Briar and ask him why he only carries a dagger.
20. Yngol Barrow -> East of Windhelm, the tomb of Ysgramor's eldest son and a unique helmet.
21. Find the Thalmor Assassin -> If you save Malborn and optionally Brelas during the Diplomatic Immunity main quest, an assassin comes later after him.
22. Delayed Burial -> Before joining the Dark Brotherhood, you can help Cicero near Loreius Farm north-west of Whiterun.

Once you have done almost everything you can do in Skyrim there's 1 thing you are left to do: Level up your character to at least level 80 so you can complete the Ebony Warrior quest, make sure you have invested a lot of points in different trees so you can try different playstyles, and start mods!

- The best way to play mods is to make a save before uploading the mod. Play the mod, and after you finish the mod uninstall it, delete the saves you made with the mod on and play another mod from where you had that original save before instaling the mod.

- Because of this, I recommend finishing every quest you can finish in Skyrim and having at least level 81 so that you would have already finished the Ebony Warrior quest and have powerful enemies as well.

- Additionally, to make sure you have finished the game 100%, you can open console and use the command saq (start all quests) to see what other quests you have missed, then reload a save before the console command and play those quests manually.

- Falskaar (very huge and famous mod apparently)
- Wyrmstooth (another huge mod)
- Summerset Isle (another huge mod that takes place in the High Elves' homeland)
- Beyond Reach (huge mode in High Rock, the Breton's homeland West of Skyrim)
- Legacy of the Dragonborn (your own museum in Solitude and Elsweyr, Khajit's homeland)
- Helgen Reborn (I always wanted to rebuild Helgen and be its mayor)
- Qaxe's Questorum (Adds over 60 new quests including rebuilding Winterhold)
- Become a Skooma Drug Lord (Walter White of Skyrim)
- Pirates of Skyrim (In case being a drug lord wasn't cool enough)
- Vigilant (A questline for the Vigilants of Stendarr)
- Molag Bal's Inferno (Challenging Boss battle and unique rewards)
- Shezarrene (Another epic hero story)

- The Blood Marked
- The Call of Cthulhu
- Here There be Monsters
- The Cyrodiil Frontier
- The Aldmeri Domain
- Morthal Pain
- Valley of Outcasts
- The Laste Refuge
- Sign of Cipactil
- Advents of Flame
- Envoys of End
- Adal Matar: The Last Stronghold
- South Dragon Bridge
- The Oblivion Strikes Back
- Fight Against the Thalmor
- The Inferno

- Into the Depths
- The Fifth Gate
- Lord Balmer's Playground
- Cyrcle of the Silencer
- A Cure for the Nightmare
- Lurking in the Shadows
- The Dead Deed
- Darkend
- The Bottomless Pit
- Blood of the Nord
- Psijic Realm
- Clockwork
- The Grey Cowl of Noctural, Undeath
- The Forgotten City
- The Tools of Kagrenac
- Moon and Star
- Path of the Relevant
- Dragonslayers
- The March of the Dwemer
- Boethia's Bidding
- The Forgotten Prince
- Agents of the Righteous Might
- The Shadow of Meresis

There are more, but these should keep you busy for a long time.

If you want to play with an already mods ready character, I posted my level 81 Breton vanilla save game on nexusmods[www.nexusmods.com]. I'm playing Skyrim Legendary Edition.

The whole game was played in vanilla, so it should be compatible with any mods you add afterwards.

Most of his skills have around 60-80 proeficiency.
- The warrior skills being all 80.
- Destruction and Restoration being 90
- The other magic skills being around 60-80.
- Sneak and Pickpocket are low, around 60.
- Lockpicking skill is around 90.
- The other thief skills are, around 80.
- Legendary skills: restoration, enchanting, smith, heavy armor, block and one-handed.

You have 9 free perks to choose. Alternatively, you can reset all your perks using the Black Books in the DLC. As I already have more than enough dragon souls.

Magic, Skills and Powers:
- A lot of spells, but not all of them.
- All shouts unlocked (two are bugged, the Drain Vitality bug from Dawnguard)
- A lot of powers unlocked (probably all of them, but can't tell for sure)

Armor and Weapons:
- Drangobone Heavy Armor, One-handed Sword and Bow.
- Home in Windhelm, there you can find:
- Dragonbone Light Armor, Two-handed Sword, Club, Dagger, another One-handed Sword, Mace.
- Companion wears Stalhrim heavy armor, dual Axes and Bow.
- All upgraded on Legendary level and with 2 enchatments.
- They are not upgraded to their maximum possible value, as I still wanted a challenge, but they are upgraded to a close to maximum value.
- There are plenty of potions and resources in your house in Windhelm to make other gear, check the chests.
- My previous gear from lower levels can be found in the wardobe inside the Dragonborn's bedroom, nostalgia.

Other significant things:
- I have the Black's Star in the inventory.
- I have all the books of Skyrim in the library in my home in Markarth.
- I won the civil war for the Empire.
- I won the Dawnguard war for the Vampires. (basically, I won both wars for the vampires)
- Wife is Ysolda and I have 2 children.
- I'm no longer a vampire or a werewolf, but you can still turn in both of them by talking to certain people.
- All the defeated Jarls can be found in Windhelm next to Jarl Ulfric's dead body.

About my game:
- I used console commands when playing, but not game breaking console commands.
- I did not leveled up my character, my gear or my skills using console commands.
- I only intervened with console commands during quests when there was a bug.
- I went back to Sovngarde 3 or 4 times, using console commands.
- Save 279 is before I face the Ebony Warrior
- Save 280 is after I faced the Ebony Warrior, his items stored in my home in Riften.

Quests Remained:
- The repetitive: dark brotherhood, companions and vampires quests.
- Locate the East Empire Pendants on Solstheim - minor quest, mostly about searching.
- Visit the Hunters at Frostmoon Crag - they only care about you if you are a werewolf, doable.
- Find evidence of Ogmund's Talos worship - how about no.
- Kill Paarthurnax - don't worry, I finished the Blade questline to get the potion before I was given the quest.
- Ebony Warrior (only if you pick the 279 save).

It's a level 81 character with a lot of proeficiency in many skills. But it's not a perfect full level character. It's a character that you can still develop as you play with him. Perfect for trying out mods with.

Miracle of Sound - Khajiit likes to Sneak

Miracle of Sound - Nord Mead

Miracle of Sound - Sovngarde Song