Adds a deep underground realm with different mapgen that you can reach with obsidian portals.
Visible player armor & wielded items.
Wilhelmines Living Nether
Adds various creatures to your Nether.
Hallelujah Mountains (AKA Cloudlands)
Giant rocks floating suspended in magnetic eddies. (skylands, islands, fantasy, giant trees)
balrog (flux's fork)
Makes stone and desert stone see through, also works with nether mod
Add monsters and dragons to your nether world.