Essential Unlockables - The Complete Guide (The Binding of Isaac: Afterbirth+) - YouTube
My Achievements Unlocked Without Winning (The Binding of Isaac Repentance) - YouTube
The Binding of Isaac: Rebirth - How to unlock Marbles/Pica Run EASY! ( Repentance only!) - Steam Lists
Endings - Binding of Isaac: Rebirth Wiki
How To Unlock Tainted Characters In The Binding Of Isaac: Repentance
The Binding Of Isaac: How To Unlock Every Character
Repentance items that are automatically unlocked are not unlocked : r/bindingofisaac
Repentance Character Unlock Sheet Guide : r/bindingofisaac
7 Secrets in Binding of Isaac Repentance Most Players Haven't Found Yet
The third (and hopefully last) Character tier list based off what they unlock : r/bindingofisaac
How to Unlock The Lost, The Forgotten, and The Keeper (All Characters) - The Binding of Isaac - YouTube
I created a table which shows the items you can unlock by killing different bosses with different characters. You can just print it out and check the items you've already unlocked. :
15 UNLOCK KEEPER - Isaac Repentance CHAOS DEADGOD 2024 - shisheyu_mayamoto on Twitch
Repentance Character Unlock Sheet Guide : r/bindingofisaac
Completion Marks - Binding of Isaac: Rebirth Wiki
The Secret of "34" - How to unlock Tainted Characters in Repentance! - YouTube
Repentance Character Unlock Sheet Guide : r/bindingofisaac