WorldEdit
sfan5

In-game world editor. Use it to repair griefing, or just create awesome buildings in seconds.

Cottages
Sokomine

Build medieval cottages with furniture, window shutters and roofs, thresh your wheat, repair your tools.

Windmill
Sokomine

Rotating sails and rotor blades for classic and modern windmills.

Minetest Game Plus
Wuzzy

Adds various simple decorative blocks, doors, panes and other items, focusing on snow, ice, luxury, bamboo and more.

Tunnelmaker
kestral

Easily create arbitrarily curved tunnels, paths, and bridges.

Bridges and handrails
Sokomine

Self-building bridge, small bridge building and handrails

BlockColor
Chiantos

BlockColor is a creative sandbox with only 8 colors.

Smart Inventory
bell07

A fast player inventory with focus on a many number of items and big screens

Itemshelf
zorman2000

Generic item shelf with 3D items on display

vexcazer
AiTechEye

Ultimate build+mine & admin tool

Floating Anchor
Starbeamrainbowlabs

ExtraUtilities' Angel Block for Minecraft in Minetest! Place structures in mid-air with ease.

Pixelart
Linuxdirk

This mod adds nodes for pixelart grouped in color palettes to Minetest

Creative for NodeCore
Warr1024

"Creative mode" for NodeCore: adds a rc_reative priv, /rs chat command, and "replica" nodes.

Bouncy Bed
FreeGamers

Simply makes beds bouncy.

Rainbow Source
Shara

Adds coloured water.

Incredible Maze Generator
orwell

This mod is a maze generator

Nyan Cat
rubenwardy

nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan

Cups
Wuzzy

Decorative cups.

Better Ice
TheFanne

Modifies ice so that it melts into water when broken, and will be melted by torches

Plastic Box
Starbeamrainbowlabs

Adds a recolourable plastic box. Fork of @cheapie's version with improvements.

Cave Explorer
Hume2

An utility for cave exploring in creative

Poly Decor
PolySaken

My spin on decorative stuff.

Letters Colors
Chiantos

Alphabets with 8 Colors Nodes.

Maths Colors
Chiantos

Maths with 8 Colors Nodes.

Colorscreens
DELTA_FORCE

Decorations that can also be used as an actual greenscreen or other colorscreen.

Symmetool
Nigel

Symmetric building tool for MineTest.

Block Exchange
BuckarooBanzay

Cloud worldedit schema exchanger

Short Names for worldedit
niwla23

Adds short number aliases to some nodes like in MC

Green Screen
Glory!

This mod adds "green screens" to minetest.