Mobkit
Termos

Entity API

Water Life
Gundul

new mobs for your river and sea water

Mob Core
ElCeejo

A Mob API meant to expand upon mobkit and bring easy to use features for creating new Mobs.

Modding Library
LMD

Multipurpose Minetest Modding Library

i3
jp

A next-generation inventory

Library Mount
Panquesito7

API Framework for mounting objects.

Villages
Sokomine

Explore the world and find villages of diffrent types. Buy a house in a village and settle down.

Tubelib2
joe7575

A library for mods which need connecting tubes / pipes / cables or similar.

Handle Schematics
Sokomine

A library to make creating and placing saved areas easier.

Arena_lib
Zughy

Library working as a core for any mini-game you have in mind

Configuration Panel
sorcerykid

API extension that allows seamless loading of mod configuration at runtime

Doors Redux
sorcerykid

A complete rewrite of the Doors mod with many additional features

Cellestial Game
LMD

Game of Life in three dimensions.

HUD Timers
LMD

A lightweight library for adding hud timers.

Climate API
TestificateMods

A powerful engine for weather presets and visual effects. Requires a weather pack like Regional Weather.

ActiveFormspecs
sorcerykid

ActiveFormspecs is a framework that abstracts the builtin formspec API of Minetest

Display Modpack
Pyrollo

Display modpack provides mods with dynamic display (signs, clocks, steles) and api to manage font and display

Mapblock Lib
BuckarooBanzay

mapblock serialization functions

Extended Tooltips
Wuzzy

Support for custom tooltip extensions for items

Beds Redux
sorcerykid

A complete rewrite of the Beds mod with many additional features

Find Biome
Wuzzy

Add commands to list and find biomes

Chat Command Builder
rubenwardy

A library to make registering chat commands easier

Controls
BuckarooBanzay

Utility library for control press/hold/release events

Raycast Bows API
runs

This is only the API. Download the Farbows mod for the bows too.

Template to Easily Make Fancy Voxelized Models
Noodlemire

Provides voxelmodel.obj, a model designed to be shaped by changing its texture, in order to easily create fancy voxelized models.

ts_workshop
Thomas-S

API for workshops

Intllib
kaeza

Internationalization library.

Moblib
LMD

Low-level high-performance entity library

Fluid Container API
IcyDiamond

Library for nodes containing fluids

Natural slopes library
karamel

Library to simply add slopes to regular nodes and include them on map generation and when changing the landscape.

Documentation System
Wuzzy

A simple in-game documentation system which enables mods to add help entries based on templates.

Cartographer
Hugues Ross

A mapmaking API.

Elepower
IcyDiamond

A powerful modpack

Fire Plus
Lone_Wolf

Allows players to be lit on fire.

Meshport (Minetest Mesh Exporter)
random_geek

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

Pova
TenPlus1

Pova gives mod makers a set of functions to safely apply overrides for player speed, jump height and gravity.

Formspec AST
luk3yx

A library to help other mods interpret formspecs.

Common Mob Interface
Byakuren

A standard modding interface for interacting with mobs

Player Physics API
Wuzzy

This makes it possible for multiple mods to modify player physics (speed, jumping strength, gravity) without conflict.

More vector helpers
Hybrid Dog

Adds more vector functions.