Mods for 1.12.1
11 mods match your filters.
Allows the player to play in an old abandoned city instead of the normal overworld
Speed up your world loading by removing unneeded chunks.
Adds >200 new structures that integrate perfectly into your world!
Fixed a Village ChunkLoading Issue
The Lost Cities addon to add more danger to the buildings.
Adds coral reef to bodies of water.
Climate control allows you control climate zones, ocean sizes, biome frequencies, and continent sizes. Make Minecraft worlds into Yourcraft worlds!
RTG Plus adds extensive and immersive variety to forests, which vary in tree composition, height, and density to RTG's extensive terrain variability, broad navigable rivers and lakes, soaring mountains, rolling hills, and sweeping plains.
A small mod that can disable some or all of vanilla ore generation (including andesite/diorite/granite and silverfish blocks)
Painted Biomes allows using image templates for the world's biome layout
Fix lava generation at Y-54 and lower