Randomized Map-specific Ores
Piezo_

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

Beautiful Boulders
regulus

Procedurally Generated Rocks with (pretty) Accurate Collision Boxes

Alien Tools
chaosomnium

Alien Tools Mod for Minetest - adds Alien Tool, Shield, biome, etc

Nyancat's heaven (reworked)
Hybrid Dog

Adds a nyanland in the sky

Sun Flowers
Hybrid Dog

This mod generates flowers which close their heads at night.

Fragments
Amaz

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

Zinc
alerikaisattera

Zinc metal, used for making brass

morebiomes
mzs.112000

A simple mod adding a few biomes to Minetest Game

New Biomes
Arkatron

If you like underground biomes, this thing is for you.

Startest
Robot10&Scheletor

This mod adds several space stuff to the game.

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.

treasures
ademant

Treasure nodes with useful items

golden lava
GigaByte

add golden lava

Sticks Stones
MikeRedwood

Makes Sticks from leaves and scatters small stones

Trucraft
mt-mods

An alternative crafting system done entirely in the world.

Underground Survival Lighting
Arkatron

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

Spawn redo
cathaya7d4

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

Fly-B-Gone!
Hugues Ross

Hides butterflies/fireflies

Obdy
Sires

Adds some pretty OP tools :)

World Borders
argyle

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

Noriel Sylvire's Minerals Core Modpack
Noriel_Sylvire

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

summer
ulla

SUMMER

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.