A game built 100% from scratch, including code, textures and sounds.
NodeCore Nature: Revised
Updated, fixed, enhanced edition of Winter94's NodeCore Nature
Grassy Goldenrod plant for Nodecore
Survival in hardcore acid-alien sci-fi themed world
Algae mapgen addition to "Minetest Game"
This combines several other mods that I consider a basic minimum starting point for worlds.
A game that aims to contain lots of environments and things.
Gaël de Sailly
A map generator with valleys, rivers, mountains and many plants.
Adds various kinds of plants, fruit bushes, fallen trees, and a whole host of foliage and other ground cover.
Adds a whole bunch of new types of trees, some bearing fruit or similar, using biome_lib for the placement engine.
A mod for Minetest to add underground realms.
Ethereal mod uses the v7 mapgen to add many new biomes to the world.