WorldEdit
sfan5

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

Edit
Johannes Fritz

Allows copying, pasting, filling, deleting, replacing and saving 3D areas

Meshport (Luanti Mesh Exporter)
random_geek

Easily export areas in Luanti to meshes for 3D rendering.

Protector Redo
TenPlus1

Lets players craft special blocks to protect their builds or disable PVP in areas.

Modgen
BuckarooBanzai

mapgen mod creator

Terraform
x2048

Adds terraforming tools to your creative toolbox

Discord-Minetest Relay
archfan7411

Mod + external program providing Discord relaying and commands.

Areas
ShadowNinja

Areas is a advanced area protection mod based on node_ownership.

Cleaner
AntumDeluge

Remove/Replace unknown entities, nodes, & items.

Streetbuilder
seckl

Build a street from given points

Extruder Tool
fgaz

Adds an extruder tool that can extend continuous surfaces towards the node face that was clicked

Public teleport location bookmarks
Hybrid Dog

Add commands to manage public positions of interest

WorldEdit Additions
Starbeamrainbowlabs

Extra tools and commands to extend WorldEdit. Currently has over 70 commands!

Permatime
ROllerozxa

Set the day of time cycle to a certain time permanently.

Bulldozer
celeron55

Driveable bulldozer for pushing nodes and flattening ground

Map Tools
Calinou

Adds various special versions of normal blocks, tools, and other map maintainer tools.

SzUtilPack
Warr1024

A collection of misc dependency-free utilities primarily for server hosts

Really Flat
rdococ

Generates superflat terrain in whatever material you choose.

WorldEdit Maze Generator
wsor4035

A maze generator

Tools Using the Node Damage and Repair System
Noodlemire

Overrides pre-existing tools to make them cause persistent node damage.

Playtime Recorder
Lejo

Use /playtime to get the time you played

MobConf
zeuner

Place, remove and configure Mobs (for now: NPCs) using chatcommands

Blockbomber Editor
MisterE

Make arenas for Blockbomber

NextGen Bedrock
StarNinjas

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

Essentials
SkyBuilder1717

Adds a lot of helpful commands for your server

Cozy Lights
SingleDigitIq

Early alpha. Improves the way light sources(torches etc) behave and allows to create huge lights, literal projectors with just a mouse click, light map will be computed for you.

Entity Modifier
j8r

Modify the model and size of entities, including players.

Remove Unknowns
Clyde

A small tool to help you clean up your world of unknown-blocks.

Classroom
rubenwardy

An easy way to manage students in-game, with support for bulk actions and macros.

Better Command Blocks
ThePython10110

Adds command blocks similar to those from a certain other voxel game.

Mapserver
BuckarooBanzai

mod for the mapserver

/giveme itemname completion
Hybrid Dog

Autocompletion of item names for the /giveme chat command

Player Factions Redo
Pixelated

Rewrites the Player Factions mod to be more efficient and easier to use

User Manager
1F616EMO

GUI to manage players

Internet Relay Chat
kaeza

Connect your server to an IRC channel, and install irc_commands to control the server from IRC

use_texture_alpha workaround
1F616EMO

Fix boolean use_texture_alpha on MT5.9+

QA-Block
bell07

A mods development / QA helper

Moderator Warnings
1F616EMO

Emphasize warnings sent by the moderation team

WorldEdit Undo
Hybrid Dog

Undo and Redo executed WorldEdit chat commands

Pick And Place
BuckarooBanzai

Pick and place utility