NextGen Bedrock
StarNinjas

Adds an indestructible bedrock layer at the bottom of the world.

Quarry Mechanics
kestral

Adds quarry mechanics to stone nodes.

Geodes
AwesomeDragon97

Adds amethyst geodes and an API for making custom geodes.

XBlocks
GamingAssociation39

Additional blocks for decoration/building

Doors without window
Taras Lavrentiev

Adds doors and trapdoors without windows to Minetest Game

Magma Conduits
FaceDeer

Removes default mapgen lava and adds widely-spaced vertical lava "veins".

MTC Chisel
Can202

Add Chisel and new decorative blocks.

Moonflower
TenPlus1

Moon Flower, when touched by the moon, it opens up a casting light.

Fantasy Biomes
AirplaneMan

Fantastical Biomes for your worlds.

Ephesus
Horka

Added ancient architectural blocks from the Mediterranean

Modern Ish
thomasthespacefox

A collection of modern-ish odds and ends.

Minetest 2D
AiTechEye

Transforms the world into 2 dimensions

Mylandscaping
Nathan.S

Lets you put up decorative walls around your gardens, and make pretty hardscapes.

ts_doors
Thomas-S

Adds doors for all kinds of wood.

More Stones
Blocky Player

Provides a variety of educational and decorative minerals and rocks.

Turret
Giga_M

adds a defensive turret

My Roofs
Don

Adds mesh roofing nodes.

Portable Chests
Bob64

Portable chests you can pick up even when there are items inside.

Underground Challenge
Hypernoot

Explore all 62 underground biomes!

Chains
X17

Adds chains to climb or decorate

Christmas Tree
ExeterDad

Adds a decorated indoor Christmas tree with wrapped gifts.

My Scaffolding
Don

Scaffolding to help you reach high places

Colored Meselamps
devurandom

Adds colored versions of meselamps, craftable with dyes

Procedural Furniture
the_raven_262

Creates furniture collections

Colored Blocks
sermow

Different colors of: stone, stone bricks, wood obsidian, and glass

Bricks Plus
X17

Adds different brick patterns

Oxidizing Copper
StarNinjas

This mod aims to make copper/bronze more realistic by making them slowly oxidize into a bluish/green block when exposed to water.

XP Redo
mt-mods

Adds experience, ranks, and doors only accessible to those above a certain rank. Not actually a redo of any mod.

The Confluence
MisterE

A luamap example - a small (500x100x500) Island in the middle of the ocean with 4 rivers that run from the center to the sea.

Cones: Traffic and Training Cones
ClassicAdam

Cones. Various use traffic cones and training cones. 3 sizes, 10 colors, 30 cones in total.

More Pickaxes
Koda_

Adds additional pickaxes to the game

Axis Tools
mt-mods

All the functionality of tinkers construct, but all in your inventory.

Reinforced Diamond Tools
ImAlreadyHere

A sword and a pickaxe that are really strong and can be crafted with diamond blocks and sticks.

Dirtcraft
dayer4b

Adds automatic crafting recipes for making most kinds of dirt

Aqua Farming
Clyde

Farming under Water, now it's possible.

Lava + Water > Stone
1F616EMO

Cool Lava into technically special stones for easier cleanup

Coconut Trees
Neuromancer

Adds coconut trees with edible coconuts & thatch blocks

Zero-Effort Custom Minerals
Piezo_

A tool for registering entire materials, complete with ore generation, tool-sets and automatically generated sprites with almost no effort required

Craftable Lava
MikeRedwood

Enables the crafting of lava from baked stone

Trails
X5Dragonfire

Allows you to make paths in grass with ground roller