Nyancat's heaven (reworked)
Hybrid Dog

Adds a nyanland in the sky

Randomized Map-specific Ores
Piezo_

Adds two randomly created ores to each world with varying properties depending on the world's seed

New Horizons
Hi_World

Adds 4 new biomes and TONS of new blocks!

treasures
ademant

Treasure nodes with useful items

Sticks Stones
MikeRedwood

Makes Sticks from leaves and scatters small stones

Obdy
Sires

Adds some pretty OP tools :)

golden lava
GigaByte

add golden lava

Alien Tools
chaosomnium

Adds Alien Tool, Shield, biome, etc.

Purple ore
X-DE

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

Sun Flowers
Hybrid Dog

This mod generates flowers which close their heads at night.

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.

Noriel Sylvire's Minerals Core Modpack
Noriel_Sylvire

An API for automatically registering recipes, nodes and ore generation.

Spawn redo
cathaya7d4

Drop-in replacement for default/spawn for more third-party biomes

Floof
Momo

Add BicBiomeCraft inspired biomes, tools, and items.

Trucraft
mt-mods

An alternative crafting system done entirely in the world.

Beautiful Boulders
regulus

Procedurally Generated Rocks with (pretty) Accurate Collision Boxes

More Coral
Nathan.S

Adds coral in more colors.

Underground Survival Lighting
Arkatron

If you like underground light in survival, use this mod, it can help that.

Mud
Blocky Player

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

Silver
Jackknife

adds silver ore and tools

Too many ores
TeufloV

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