Mesecons Stealthnodes
Clyde

Register your own Ghoststones.

Archaeology
SkyBuilder1717

Adds an looting and API in archaeologing

Debugging Console
sorcerykid

Provides an in-game HUD to easily monitor debug output

Trucraft
mt-mods

An alternative crafting system done entirely in the world.

Loot
Byakuren

A loot framework.

Minetest Teams
pl608

simple multiplayer team system

Noriel Sylvire's Minerals Core Modpack
Noriel_Sylvire

An API for automatically registering recipes, nodes and ore generation.

Scripted World Editor
Neuromancer

API that allows you pass in scripting tables to fill a series of shapes of different sizes with different nodes

Discrete Player API
Hume2

A library for games which attaches players to node grid

Phonics Library
Neuromancer

Provides a library for creating Phonics (Learn how to read) mods in different languages.

Minebase Core
ThatCommand

Adds APIs and new dynamic functionalities.

Library Mount
Panquesito7

API Framework for mounting objects.

Telegram
neko259

Integration with telegram messenger chat

Natural Entities
nurd3

A lightweight API for spawning random entities

DeltaTime
SkyBuilder1717

Adds deltatime API

Local Time and Date Api
Bob64

This is a minetest mod that provides an api for other mods to use to get a user's preferred date and time format/time zone based on their configured settings for this mod.

ConfigFileLibrary
Tomlaus

A library that allows loading and saving data from config files.

Oreveins
ApolloX

A node which produces ores

Walkover
lordfingle

A library to make it easier for developers to detect on_walk_over