Minercantile
Mathias

Economy featuring a primitive supply and demand system for exchanging goods.

Kill Button
niwla23

Allows you to kill yourself from the UI

Advanced Playtime
zanderdev

Keeps track of playtime for all players in your world. Notifies you how much playtime you have occasionally.

Topaz Items
WINNIE

Topaz Items for Minetest

Armor Monoid
Byakuren

A player_monoids monoid for armor

Underground Survival Lighting
Arkatron

If you like underground light in survival, use this mod, it can help that.

Minetest Email
MrFreeman

Adds email style inboxes to Minetest.

Player Nametags
LMD

Adds player nametags floating above players.

Matterbridge Player Events
cj_clippy

Sends a message to the matterbridge when a player joins/parts

Ascend
kestral

Ascend by chat command, if possible.

Minetest HTTP API QoS control queue
SX

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

Sausages
1F616EMO

Sausages! Yum!

persistent_monoids
fluxionary

player_monoids that persist between player sessions and server restarts/crashes.

Breadcrumbs
FaceDeer

Path marker signs for use when exploring a twisty maze of passages that are all alike.

Roadway
X17

Adds simple roads in 4 sizes.

Kick Player on Death/Respawn
Volik

Kicks player on death or respawn.

Math blocks
Giulio

Adds decorative math blocks to help in teaching

Chat Games
Impulse

Get rewards for answering questions in the chat.

Moth
iarbat

Adds moths which can send messages (from Lord of the Rings)

LocalChat
qPexLegendary

Adds local and global chat

Obdy
Sires

Adds some pretty OP tools :)

Item Holders
Jose_ManuelS18

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

Colored Chat Text
Bob64

This makes the minetest chat messages a different color depending on what you set it to in the settings.

Rotting Wood
Polynium

Causes wood to slowly rot while exposed to water

Scraps
Goops

Allows to recycle metal tools

Antipyre
Warr1024

Safety net against falling off your island

Copy From Chest
zeronumbers

Adds server command copy-from-chest that copies items from chest at x y z to player.

Minetest Engine Stats
mtvisitor

Get some basic stats of MT Engine. (must >= ver5.8)

Discrete Player API
Hume2

A library for games which attaches players to node grid

Upgrades
niwla23

Adds effects to players for a short time

Chat Games API
Impulse

An API to build chatgames like those in the chatgames

Plastic Box
Starbeamrainbowlabs

Adds a recolourable plastic box. Fork of @cheapie's version with improvements.

Keep Inv Random
Tomlaus

There is a 10% chance that your inventory will be deleted when you die, even if keep inv is on.

mTimer
Linuxdirk

Ingame timer for showing current playtime, current day time, ingame time, etc.

Callbacks API
ANAND

callbacks_api is a framework for registering callbacks if the callback registration function exists, else returns gracefully.

K Wider Hotbar
ketwaroo

Increases the number of hotbar slots by displaying exta inventory rows

blueberry_juice
MR_breaddz

blueberry juice

Staff Channel
_Xenon

Write messages only to staff

Survival
Nathan.S

Adds several survival related items.

Openion Yeast
Wovado

Adds Yeast and a Yeast Barrel