Thanks for the responses. It would appear after browsing a few mods and seeing the replies that there isn't the kind of mods I was looking for (or is there?). Someone said in another thread that there was a mod which added to the Mistlands biome.

However the mod I looked at added some enemies to the unfinished biomes but I was looking for something more complete I guess. Like a mod that completely fleshes out some of theunfinished biomes.

The QOL mods look cool dont get me wrong. But Im looking for mods that fill in all the empty space our worlds have with the incomplete biomes.