Oreveins
ApolloX

A node which produces ores

Epic
BuckarooBanzai

Enhanced Programmer for Ingame Control

House Windows
DiamondPlane

Adds windows for your house

Minetest HTTP API QoS control queue
SX

Improve quality of important HTTP requests by grouping requests into service quality buckets.

Modding Library
LMD

Multipurpose Minetest Modding Library

markdown2formspec
Just_Visiting

A markdown to Formspec Utility

Sounds
AntumDeluge

A set of free sounds & API.

Chat Command Builder
rubenwardy

A library to make registering chat commands easier

Database Manager
AFCM

Database Manager API

Complete and Total Lua-Only Inventory Rewrite
Noodlemire

Creates a completely custom inventory system, which doesn't rely at all on any of the usual UserData objects.

Autobox
Just_Visiting

Auto Collision/Selection Loading Boxes

HUD FS
Luke

A library to make HUDs from formspecs

World Data Manager Library
AntumDeluge

A library for managing data files in the world directory.

Smart Vector Table
Noodlemire

API that adds a way to create tables indexed by 3D Vectors.

Simple Models
AntumDeluge

Very simple models.

Tools Using the Node Damage and Repair System
Noodlemire

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

Node Damage
Noodlemire

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

Placeable Buckets for Catching Rainwater
Noodlemire

Allows empty buckets to be placed as nodes in order to collect rainwater.

SzUtilPack
Warr1024

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

Mapblock Lib
BuckarooBanzai

mapblock serialization functions

Mob Core
mt-mods

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