Obdy
Sires

Adds some pretty OP tools :)

Purple ore
X-DE

Adds new purple ore to floating islands and caves from height 200 to 31000.

Dirt Tunneler
Neuromancer

Makes dirt deeper and you can tunnel through it just by walking through it. Press spacebar/shift to tunnel upward/downward with auto placed ladders.

Trucraft
mt-mods

An alternative crafting system done entirely in the world.

TerraContent Crimson
AirplaneMan

Introduces the Crimson to your worlds.

Floof
Momo

Add BicBiomeCraft inspired biomes, tools, and items.

Silver
Jackknife

adds silver ore and tools

Mud
Blocky Player

Adds stylish mud blocks and even blocks you can walk through. Setup traps, secret rooms and much more!

Too many ores
TeufloV

This adds 53 new ores. But most of them are useless.