Ancient Ice Stuff
Robot10&Scheletor

Adds a new powerful ore to the game

Advanced Biome Decoration Modpack
EmptyStar

A collection of advanced biome decorations

World Borders
argyle

Add impenetrable barriers to the sides and bottom of the world.

More Coral
Nathan.S

Adds coral in more colors.

My Treasure
Don

Adds treasure chests around the world

New Horizons
Hi_World

Adds 4 new biomes and TONS of new blocks!

Archaeology
SkyBuilder1717

Adds an looting and API in archaeologing

Tac Nayn
GreenXenith

Adds Nyan Cat's evil twin, Tac Nayn (and a gray-scale rainbow).

Randomized Map-specific Ores
Piezo_

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

Kitty/Kitto Ores
nemokitty9

Nemokitty9's own ore pack. Includes Tools!

Noriel Sylvire's Minerals Core Modpack
Noriel_Sylvire

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

Nyancat's heaven (reworked)
Hybrid Dog

Adds a nyanland in the sky

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.

Purple ore
X-DE

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

Beautiful Boulders
regulus

Procedurally Generated Rocks with (pretty) Accurate Collision Boxes

golden lava
GigaByte

add golden lava

Sun Flowers
Hybrid Dog

This mod generates flowers which close their heads at night.

Trucraft
mt-mods

An alternative crafting system done entirely in the world.

Unstable Caves
M BLOC

Some stones may cave in if punched, making underground expeditions more risky.

treasures
ademant

Treasure nodes with useful items

Obdy
Sires

Adds some pretty OP tools :)

Sticks Stones
MikeRedwood

Makes Sticks from leaves and scatters small stones

Underground Survival Lighting
Arkatron

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

Fly-B-Gone!
Hugues Ross

Hides butterflies/fireflies

Spawn redo
cathaya7d4

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

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.