For power users, save editors can do more than just check boxes.
Warning: Messing with "Floor IDs" or "Room layouts" can cause softlocks. Stick to progression flags and persistent unlockables. The Binding Of Isaac Repentance Save Editor
You don't have to go from 0% to 100% overnight. Smart editors use the "Partial Unlock" method. For power users, save editors can do more
Scenario: You want to unlock Death Certificate (requires finding every single item in the game at least once). You don't want to cheat the item into existence, but you also don't want to find Marbles or Breath of Life. Warning: Messing with "Floor IDs" or "Room layouts"
Solution: Use the editor's "Item Picker" to mark 99% of items as "Collected," but leave 3 items uncollected. Then, you only need to find those 3 items legitimately. This preserves the "hunt" feeling while removing the impossible RNG.
Scenario 2: You want to play as Tainted Lost but you hate the Greedier Mode grind.
Best for: Modifying your current run or starting stats.