Promise
mt-mods

promise library

Dungeon loot chests
X-DE

Adds loot chests, a command to prevent spawning loot in the chest so you can save a schematic with a loot chest, adds 2 functions to create loot in other chests

Mobs Redo API
TenPlus1

Simple and feature rich API to quickly add mobs into your world.

Libox
frogTheSecond

A sandboxing library

AirUtils
APercy

A lib for airplanes and some useful tools

i3
mt-mods

A next-generation inventory

Luamap
MisterE

An easy-to-use api for lua mapgens that takes the pain out of mapgen coding. Focus on mapgen logic, not on voxelmanipulation.

Item Holders
Jose_ManuelS18

Adds 'Item Holders', blocks that hold your items in display, also provides a API.

Interactive Item API
Jose_ManuelS18

Provides an API to make it easier to implement items' inner workings.

Epic
BuckarooBanzai

Enhanced Programmer for Ingame Control

Isogen
BuckarooBanzai

Generate isometric images from ingame builds

Mapblock Lib
BuckarooBanzai

mapblock serialization functions

Natural Entities
nurd3

A lightweight API for spawning random entities

Flow
Luke

A formspec library that automatically positions and sizes elements

Minetest test framework
BuckarooBanzai

Provides an api to register test functions for integration-tests.

Controls
mt-mods

Utility library for control press/hold/release events

Tips
1F616EMO

Send tips to newcomers