Realistic Terrain Generation Mod for Minecraft 1.9.4 Mods adds a new world type which generates realistic terrain. It doesn’t add new blocks. It doesn’t add new mobs. It doesn’t even add new biomes. It simply generates more realistic-looking terrain for existing Overworld biomes (including those added by other mods).
Download link: Realistic Terrain Generation Mod for Minecraft 1.9.4/1.8.9
Read more: Minecraft 1.9.4 Mods