Magma
SuperStarSonic

Adds volcanoes, lava vents and new magma blocks

Tac Nayn
GreenXenith

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

treasures
ademant

Treasure nodes with useful items

Fragments
Amaz

A mapgen with a goal, with things needed to advance to the next level.

Advanced Biome Decoration Modpack
EmptyStar

A collection of advanced biome decorations

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.

Boulders
Neuromancer

Adds pushable boulders which spawn in dirt & stone. They tumble when they wind up on top of each other and cause damage when they fall on you.

golden lava
GigaByte

add golden lava

Sticks Stones
MikeRedwood

Makes Sticks from leaves and scatters small stones

Noriel Sylvire's Minerals Core Modpack
Noriel_Sylvire

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

Obdy
Sires

Adds some pretty OP tools :)

World Borders
argyle

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

Purple ore
X-DE

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

Trucraft
mt-mods

An alternative crafting system done entirely in the world.

Boulder Dig
Neuromancer

Creates gameplay for the game Boulder Dig (inspired by Boulder Dash). Find the boulders and gems scattered throughout the regularly generated world. 2nd option is more densely packed levels.

Beautiful Boulders
regulus

Procedurally Generated Rocks with (pretty) Accurate Collision Boxes

Spawn redo
cathaya7d4

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

Randomized Map-specific Ores
Piezo_

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

More Coral
Nathan.S

Adds coral in more colors.

Fix floating sands!
1F616EMO

Avoid hanging sands and gravels

Fly-B-Gone!
Hugues Ross

Hides butterflies/fireflies

Floof
Momo

Add BicBiomeCraft inspired biomes, tools, and items.

Easter Eggs / Ostereier
Ineva

Adds various coloured eggs for Easter!

Lucky Block Ore
ems111

Adds Lucky Block ores to world.

Aotearoa
Eris

Fork of aotearoa by Dokimi. Complements the default map biomes with Aotearoa, land of the long white cloud, New Zealand.

Warning: Non-free media.

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.