intersecting 0.4.0 by paramat
For Minetest 0.4.12 and later
Depends default
Licenses: Code WTFPL, textures CC BY-SA 3.0

Unlimited tunnel and magma tunnel networks created from 3D noise.
3D underground 'biomes', each with a differing mix of 2 intersecting tunnel systems, the biomes create a few dead ends.
Mostly separate from this is a larger scaled magma tunnel network, if these magma tunnels come to surface in water, default lavacooling creates obsidian tubes.
Optional glowing lux ore craftable with 8 glass nodes to 8 lights, lux ore also spawns in desert dungeon walls.
You can use this with or instead of normal caves, disabling normal caves removes the lava caves and some features in the landscape.