Quick note: Percentage boosts shown are additive. So if you have 6 manuals that all provide 50% attack boosts for a total of +300%, a 60% attack boost only raises that to 360% - so effectively a 15% boost to total attack. Defense and hp work similarly, but there are far fewer %boosts to them, making those comparably more valuable.

Buffs are multiplicative - a 200% attack buff will raise total attack by 200%.

S tier: Swordsman

Swordsman gives 7% healing on crit, which is amazing, and gives +200% damage - boosting its own healing in the process. The combination of damage and sustain is nuts, and makes this easily the best bloodline.

A tier: Ice Troll,Taiyi Golden Immortal, God of Spirits

Taiyi Golden Immortal is the best DPS spec, giving a 10% stacking attack bonus with no limits. Scales basically as long as you are in combat. If you're killing things too fast it might not be as useful - but that's a problem you want to have.

Ice Troll and God of Spirits are both survivability. Ice Troll gains a stacking defense boost that scales with its own additive defense percent boost, bringing defense to unequaled levels. God of Spirits has an insane physical defense boost, and a stacking magic defense boost that undoes its innate minus.

God of Spirits is probably the winner on a sword&shield user, while Ice troll is a general winner on everyone.

B tier: King of Sirius, Superman, Ultra Brave, Mummy, Ancestor of Vampires, S-virus, Grand Lord

These are all fine. Good boosts, just not as good as what you can get in S or A tier. Ancestor of Vampires gets a special note because it's probably the best healing bloodline if Duckweed and Swordsman get nerfed (which they really, really should). It also gains the most from purple to gold, becoming a very solid healing bloodline.

King of Sirius is an amazing bloodline because of the attack speed. This increases proc rates on things like Swordsman, Vampire, and Taiyi. There's a passive attack speed proc in the bloodline as well as one for transforming, some of the only attack speed buffs in the game. Sadly the +50% HP stacks additively with the +200% HP from Promoting, so it's net only 17% increase to real HP if you're getting the gold bloodline on someone promoted. Bump it up to A tier on someone who isn't promoted though (when paired with another bloodline that has on-hit or on-crit procs).

Superman gets a nod for just being a TON of stats everywhere.

Grand Lord is a good HP boost but not as good as Sirius, and even on a tank the low chance and 10 second cooldown make the AOE damage proc just mediocre. The flat scaling defenses are completely negligible (you should have 10,000+ defense at a minimum by the time golden bloodlines are even available).

S-Virus is really good damage, but... see Taiyi Golden Immortal. The health restore happening every 3 minutes is way too slow to matter - I wish it would block a lethal hit and restore 30% with a 180 second cooldown.

Mummy is a 15% damage reduction for everyone, making it fine on a back liner. Damage is whatever, but is a nice addition to Hanba. I would have rather had 20% attack reduction to enemies, but maybe that was too strong (it would be very good).

C tier: Elemental Rule, Emperor Priest, Holy Light Angel

Elemental rule is pretty worthless because there's 7 staff manuals, meaning the % gain is almost nothing. The meteor swarm proc should be AOE, but a 10% chance is pretty minor and overall it's only okay. Taiyi Golden Immortal etc. etc.

Emperor Priest has derpy summons but the 10% chance to stun is actually an okay damage reduction. That keeps it out of D tier.

Holy Light Angel has a percent defense boost, which is okay, but better is available in all other tiers. It's a roleplay bloodline. Superman is better in literally every way except the RP wings (could change if we learn something about belief, but right now I have no idea what that does)

D tier: Demon King, Phantom Fallen Angel, Ancestor Spirit
Demon king is a summon and a negligible damage boost. Yawn.

Phantom fallen angel is a low boost to damage and RP wings. Get if you want black wings I guess?

Ancestor Spirit is an okay dps boost, but Taiyi Golden Immortal rapidly outscales it even at 10 stacks, and it scales forever. Crit damage is not as good as infinitely scaling damage. Has some damage procs that are better with bows, but Taiyi and Swordsman are still just better overall. Since it also has nothing but damage, it falls into D tier.

F tier: God of Heaven
+225 to all stats? It's not even close to as good as Superman. Oh and 125 of the stats come from a buff to add insult to injury. You could literally multiply these values by 10 and it'd only go up to B tier.