Pryaxis/TShock

A mod to make and play Terraria mods. Supports Terraria 1.4 (and earlier) installations

Empowering everyone to host fast and efficient Minecraft servers

PufferPanel is an open source game server management panel, designed for both small networks and personal use

A server software reimplementation for a certain anime game.

26.2 Lightweight Minecraft server

Custom server software for Minecraft: Bedrock, built from scratch in PHP, C and C++

Cloudburst Nukkit - Nuclear-Powered Minecraft: Bedrock Edition Server Software

A simple and easy to use mod manager for several games using Thunderstore

TEdit - Terraria Map Editor - TEdit is a stand alone, open source map editor for Terraria. It lets you edit maps just like (almost) paint! It also lets you change world settings (time, bosses downed etc), edit chests and change sign, make epic dungeons, castles, cities, and add rewards for your adventurers!