I wrote this guide based on my experience from played in several server and some test in Single player mode, but not from any official source or digging around the game files.
I just saw that sometime looting is way better than grinding for the resource, level up your skills to make the items yourself, looted items usually have better quality too. Another way is upgrading and buying from vendors but still looting is way easier (with RNG chance of course).

Check my video for other detail:

They might be your biggest problem, wrecking your base and killing your hard tamed creatures. But it can also be the greatest gifts blessed by the DnL gods. Here is six types of meterite you can find over the land of Archos (I just call them Lvl 1 to Lvl 6 - Not an official name).

The content inside the meteorite are several types of ore and the higher level it is, the more chance you can get elemental core and higher level of ore (sulfur, stone > copper > iron > mithrill > dark stone, light stone). The amount of ore is so little compare to mining so they might not be worth picking up.

The dark special type of dark enemy (like Dark Earth Elemental for Lvl 6) sometime doesn't spawn and there is only Dark Fallen spawn.

Lvl 1:

• Color: Gray/white/yeallow? (whatever, it looks dark and also lame)
  
• Content: low level ore like rock, sulfur (never see an elemental core in it)
  
• Enemy: Dark Fallen (the skeleton)
  
• Player level required to open: 5

Lvl 2:

• Color: Green
  
• Content: Ore like iron, copper, rock has a small chance of containing elemental core
  
• Enemy: Dark fallen, Dark Wraith (low chance)
  
• Player level required to open: 15

Lvl 3:

• Color: Blue
  
• Content: Iron, copper, mithrill, and more core
  
• Enemy: Dark Fallen, Dark Wraith (higher chance)
  
• Player level required to open: 25

Lvl 4:

• Color: Purple
  
• Content: Ore, dark stone, light stone, and more core
  
• Enemy: Dark Fallen, Dark Fire Elemental
  
• Player level required to open: 35

Lvl 5:

• Color: Orange
  
• Content: Ore (not sure), Dark stone, light stone, and more core
  
• Enemy: Dark Fallen, Dark Wind Elemental
  
• Player level required to open: 45

Lvl 6:

• Color: Red (Crimson Red)
  
• Content: Ore (not sure), Dark stone, light stone, and more core
  
• Enemy: Dark Fallen, Dark Earth Elemental
  
• Player level required to open: 60

The dark enemies can drop valuable loots and most of the time we will go after the loots. They have a high chance to drop bone, ice cube, fur, stone arrow, stone hook arrow and lower chance to drop items specific to enemy type like saddle, weapon, armor, clothe. The higher tier of enemy drop higher tier of items.

Here the list of the Dark enemies and the items you can get from lower tier to higher. Note that you tamed creature sometime will automatically get the loot, but some time will and the Dark Wraith and Dark Fallen body can be eaten by your tamed, so if you want to get the loot, you might avoid hitting their body with your tamed.

The quality of the item (Craftable, Common, UnCommon, Rare, Legendary) and the durability are random but will be better than your crafted one.

1. Dark Fallen:
- Items: Bow , Leather Armor, Druidic Staff (2nd Tier), Throwing knife, Recall spell, Boar saddle
- Body can be harvest with a carnivore tame to get Ice cube, Bone, Rotten meat.

2. Dark Wraith:
- Items: Druidic set, Druidic staff (2nd Tier), Lvl 1 Spell (rare), Iron tools, Hammer, Gut Stag saddle, Dear reins.
- VERY RARE CHANCE of the Ghost Scythe
- Body can be harvest with a carnivore tame to get Ice cube, Bone, Rotten meat.

3. Dark Fire Elemental
- Items: Iron tools, Crossbow, Hammer, Spear, Iron knife, Saddle: Wyvern, Lava Tiger, Panther, Longhorn, Spell Lvl 2 (rare)
- Body can't be harvest by your tamed, you can use tool (Iron axe, pick axe, hammer...) to get sulfur, magic shard, fire element core.

4. Dark Wind Elemental
- Items: Iron tools, Crossbow, Celestial Staff (Tier 3), Hammer, Spear, Lvl 3 Spell (rare), Saddle: Griffin, Lava Tiger, Panther, Kodo, Bear
- Body can't be harvest by your tamed, you can use tool (Iron axe, pick axe, hammer...) to get charcoal, magic shard, air element core.

5. Dark Earth Elemental
- Items: Iron tools, Crossbow, Battlemage Staff (Tier 4), Hammer, Spear, Lvl 3 Spell (rare),Saddle: Infernus Dragon, Frost Dragon, Yeti, Bahamoth, Mastodorn, Nidhog.
- Body can't be harvest by your tamed, you can use tool (Iron axe, pick axe, hammer...) to get rock, magic shard, earth element core.

Through the game, at the certain stage, you might want to go and hunt for the loot instead of creating item yourself. It will take some risk and you don't always have the item you looking for (if you don't spent enought time or out of luck and die + lost tamed). But some of the item will be worth the risk.

Tips: Use Brimstone pieces to increase cold resistant, and Ice wind pieces to increase heat resistant. You don't need the whole set, just 2 pieces is good enought for most case. For the night at the snow mountain, you might need 3 pieces of Brimstone.

1. Floating islands:

Difficulty hard, prefer Mid to Late game (when your lvl is over 35), you will need a flyer to get their, and might bring a good tame to fight (Recommend Panther, Lavatiger) and plenty of meat for them to heal. The Air Elementals in there are neutral and can help you fight the Dark enemy.
There will be drop every 5-10 minutes, the drop from Lvl 2 to Lvl 5. So you 'll have a chance to get a griffin saddle, at early stage, when you still haven't have enough skill to make Chao Essence and the Saddle it self, it can be very useful. You also have better chance to get saddle for Lavatiger, Panther.
It's pretty cold in here so you'd better bring food, one or two pieces of Brimstone.
In the free time you can kill and harvest the Air Elemental for core and charcoal and make some stone hook arrow there.


2. The Dark Invasion

Defficulty: Very Hard, prefer Late game, when you're above lvl 40 and have some really good tame like Infernus Dragon, Frost Dragon. With Panther, Lavatiger, Griffin, Bear... you should team up with other.

The event is RNG or can be triggered by activate 3 Dark Altar. The worst thing with this event is the game hasn't been optimized for the area that the event happens. And there will be alot of enemy (Dark enemy, Panther, Nidhog, Wolf, Bargesh....) so there will be lag, frame drops and event crash. And if you crash, you will mostly die and you tamed also die because there is no one control them.

So first, if you want to keep the tame, use the Summon Stone on them, bring meat to force feed them. Put 1,2 Resurrection Altar or Canopy near by.

The event last one game day, the meteorite drop by wave, each wave has about 15 meteorite lvl from 2 to 5 (never seen any Lvl 6 in there).

To activate the Dark Invasion, craft Soul Of Darkness at the Dark Altar (1 Earth Element core, 1 Fire Element Core, 1 Dark Element core each), and use 1 Sould Of Darkness to activate by press "Magic Energy Transfer" (NOT Active Altar, don't know why?)


Note: The meteorites in the Dark Invasion don't require player level to open, not sure it's a bug or feature.

3. The Volcano

Around the "Lava Shine Sould Node" in the Volcano.

There are 4 spot can spawn lvl 5, lvl 6 meteorite, and some other spot spawn lvl 3, 4, 5. But they don't drop very often, maybe one time in game day. You can put an outpost with a griffin and respawn there to check it once, twice a game day. The lvl 5, 6 usually drop at the same time, so in one trip you can check all of them.




I added location and screen shot (from my play in official PvE server).

Difficulty: Very Hard, perfer late/end game, depend on server setting the number of enemy can be low, but there will be Fire Imp, Fire Elemental, Lavatiger, Bahamut in here, they are pretty tought, and the Dark enemy is very hard now. It 's very hot in there so bring at least two Ice Wind pieces to wear (put it in the container of inside the Tamed inventory so you can teleport back and forth). Same as the Dark Invasion, if you go solo, prefer one of the Dragon, or you can team up with good Griffin.

These are end game loot so you might have to try alot of time before you can get one, but a high quality dragon saddle might worth it.

- The Infernus dragon might drop lvl 3 Fire Bold (rare, the dev might removed it in the current patch)
- The town guard is hard to fight but they drop very good armor set, so if you're confident, try to get some.
- The Elite Goblin has a small chance of droping the Goblin club, really good for taming, so look out for them.

• 2017/08/19: First version
  
• 2017/08/26: Added more detail for Volcano drops, lvl require to open Meteorite in Dark Invasion
  
• 2017/08/31: Due to the patch in 2017/08/30 (v 100.6040) the wild creature, especially the Dark Enemy got a big buff and very tough, so I update the recommend tamed for each drop location.