biome pool world type

Single biome is great, but theres only so much you could do with it. If you could select as many biomes as you would like (if you didnt select any, it would just generate plains). that would be much preferred (for example, one could use only biomes with villages, or only snowy or desert biomes) or make a vast ocean with mushroom islands. this would be a great improvement upon the single biome world type.

This would also change how the "biomes explored" achievement works, as it would only requre the biomes that are allowed to generate instead of all biomes (including the ones that arent allowed to generate)