What Did You Say??
AmericanHuston

Listens to what you say using python, and then causes things to happen in game!

Coord Hud
ergolyam

Per-player HUD showing current coordinates with draggable sliders to set position and size.

Goxel Tools
MisterE

Allows using goxel to create Luanti builds. Saves a palette of node colors for import into Goxel and allows importing Goxel models made using said palette.

Terramod-Staff
Bapt-tech

Many commands and functions for admins and moderators

Node Damage
Noodlemire

Enables nodes to be partially damaged, and to be repaired afterwards.

Global Bulletin Boards
FaceDeer

Allows creation of global bulletin boards where players can post public messages

item_monoids
fluxionary

an API for controlling item properties via monoids

Notices
LandarVargan

Adds chatcommands server staff can use for announcements

Public Death Messages
Thresher

Adds toggleable and unique death messages for when a player dies

news
Giga_M

adds an editable news section when a player joins

Tune JIT
rudzik8

Tunes LuaJIT parameters to improve server performance by preventing constant GC

InvManager
IlzumiZeminori

Allows to check and remove items from players' inventories

Shop Dialog
1F616EMO

Formspec-based shop dialog

IntelligenceFramework
PlamiumAI

Provide an AI RNN API for developers.

LuaJIT verbose mode
frogTheSecond

Imports the same module as "luajit -jv <filename>"

Tasks Framework
AntumDeluge

Framework for adding tasks & quests.

Node Meta Manipulation
AntumDeluge

Manage node meta data

Poly Decor
mt-mods

My spin on decorative stuff.

Pattern Blocks/festive Blocks
Eternal_plasma

Adds New Bright Blocks

Staff Channel
_Xenon

Write messages only to staff

Ben's Drop Randomizer
MissingTextureMan101

A game agnostic node-drop randomizer

itemshelf (Fork)
nac

Generic item shelf with 3D items on display

Pos Marker
1F616EMO

Add markers that can set and get via chatcommand.

DataMiner
sorcerykid

DataMiner is an analytical tool for server operators with a feature-rich API for customized report generation

Static compass
Sokomine

Compass block that can be placed and shows you where north is.

RandomTP
Bapt-tech

creates /rtp command and allow you to create your owns random teleport places

Burnable Diamonds
Hypernoot

Make diamonds useable as fuel

Nodecore Fairy Chimneys
Winter94

Adds geological formations called 'hoodoos' or 'fairy chimneys' to your worlds.

Snow Cones
GreenXenith

Some simple flavored snow cones.

Slingshot
AntumDeluge

Slingshots that can throw inventory items as ammunition.

blueberry_juice
MR_breaddz

blueberry juice

action queues
fluxionary

provides an API for queuing things for batch processing w/ various ways to specify the batch "size".

Replacements
BuckarooBanzai

Replacement/placeholder blocks intended for schematics

deploader
LuantistDork

Simple mod API that automates dependency-specific behaviour using a folder-heavy approach.

Kill History
LMD

Adds a kill history

LWComponents Spawners
mt-mods

Register spawners for lwcomponents.

Usable Nodes
Volik

Adds usable nodes, such as kill block, or move block.

Rivets
Silver Sandstone

Adds rivets for decoration or locking blocks.

Random (Useful) stuff
pl608

A library that adds well... Random Stuff

Advance ore API
Sere Motsatt

Create complex minerals the easy way