This is the project I put together to support my work on the "valleys" C++ mapgen. It's based on Gael de Sailly's original Valleys Mapgen, though most of the code has diverged.
Valleys Helper adds a few, more natural-looking trees, some new (purely decorative) soil types, water plants, coral, little wooden houses, glowing plants, rocks, cave biomes, and whatever I feel like at the time. It uses standard, V7 biomes and is very compatible with other mods. The cave work is based largely on HeroOfTheWinds' Underground Realms.
This mod is, and will always be, a work in progress. I don't advise anyone to put it on a serious server.
Code License: GPL3/WTFPL (and other licenses I'll note where I use other's work)
Textures License: same as above
Dependencies: default, flowers?, stairs?, integral trees?
* You must use the "valleys" mapgen from a recent build of Minetest.
Source code: https://github.com/duane-r/valleys_c
Downoad: https://github.com/duane-r/valleys_c/archive/master.zip
The overworld:
The underworld (falsely lit):
Note that in order to avoid flooding the huge caves, this mod will disable random lava and water in your valleys mapgen settings. It places lava and water in the appropriate cave biomes, but not in huge caves.