Randomized Map-specific Ores
Piezo_

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

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.

Beautiful Boulders
regulus

Procedurally Generated Rocks with (pretty) Accurate Collision Boxes

Nyancat's heaven (reworked)
Hybrid Dog

Adds a nyanland in the sky

Kitty/Kitto Ores
nemokitty9

Nemokitty9's own ore pack. Includes Tools!

Purple ore
X-DE

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

World Borders
argyle

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

golden lava
GigaByte

add golden lava

morebiomes
mzs.112000

A simple mod adding a few biomes to Minetest Game

Fix floating sands!
1F616EMO

Avoid hanging sands and gravels

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.

New Biomes
Arkatron

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

Easter Eggs / Ostereier
Ineva

Adds various coloured eggs for Easter!

Sun Flowers
Hybrid Dog

This mod generates flowers which close their heads at night.

Tac Nayn
GreenXenith

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

Obdy
Sires

Adds some pretty OP tools :)

Spawn redo
cathaya7d4

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

Underground Survival Lighting
Arkatron

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

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.

Trucraft
mt-mods

An alternative crafting system done entirely in the world.

Fly-B-Gone!
Hugues Ross

Hides butterflies/fireflies

Sticks Stones
MikeRedwood

Makes Sticks from leaves and scatters small stones

treasures
ademant

Treasure nodes with useful items

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.