This mod automatically resolves ID conflicts for blocks, items, and enchantments. Put it into mods directory and it makes things just work.
It’s a simple mod with only three classes; no gui, no special config, just one file with a list of registered IDs. The file is Idfix.txt, in same directory as your Minecraft.exe.
It works well with a bunch of mods I downloaded (the only one that doesn’t is magical crops mod, because it’s broken). It’s also a bit faster: for my list of mods, with ID Resolver it takes 31 seconds to launch, while with my mod it’s 24 seconds.
To clarify: this mod does the same thing as ID Resolver by ShaRose, and is inspired by it, but without GUI, and without bugging you to press that “assign all in reverse” button.
There are no screenshots because there are no visual changes.