Familiar Tier List sans Orbitals/Spacebar/Extra Lives/Trinkets

[B. B.]

S+: Dark Bum
S: Lil' Brimstone, The Relic
S-: Daddy Long Legs, Rotten Baby

A+: ???'s Only Friend, Demon Baby, Dry Baby, Gemini, Juicy Sack, Lil' Haunt, Little Gish, Punching Bag, Smart Fly, Little Chubby(borderline A+)
A: BBF, Little Steven, Mongo Baby, Samson's Chains, Sissy Long Legs
A-: Bomb Bag, Guppy's Hairball, Harlequin Baby, Headless Baby, Leech, Little C.H.A.D., Mystery Sack, Rainbow Baby,
Robo Baby, Sack of Pennies, The Peeper

B+: Bum Friend, Dead Bird, Ghost Baby
B: Best Bud, Bob's Brain, Brother Bobby, Isaac's Heart, Robo Baby 2.0, Sister Maggy
B-: Abel, Cain's Other Eye, Holy Water

based off the r/bindingofisaac item tier list

[Hedonism]

Dark bum s+ ?! I wouldn't agree with that if you don't get hit a lot it become useless after 2/3 payout

Li'l brim, daddy and rotten baby are the best imo .

[B. B.]

The thing about Dark Bum is that he allows you to easily maintain 12 hearts, and he's still very useful if you're not getting hit consistently. You can cover up for any dumb mistakes and return to full health. He's S+ because it's very difficult to die when you have him. Daddy, Lil' Brim and Rotten Baby are cool because they can deal nice damage, but they don't quite win you a run like Dark Bum does.

[Solo Death]

Bobb's Brain is A+ if you know how to use it. If you actively try to not blow yourself up with it, you never will, and it adds a ton of damage to your build. Guppy's hairball should go down to B+. Frankly it'd be B- imo were it not a guppy piece because it's so awkward to use.

Other than that, I agree with this list.