ArcHub: Gaming
FMHY.net/gaming - free gaming directory.
LibreGameWiki.org - the free gaming encyclopedia.
FOSS Games
Awesome open source games [website]
Awesome game remakes [website]
Luanti - Like minecraft, but better
Cataclysm Dark Days Ahead - impressively realistic survival crafting post-apocalypse RPG/roguelike
Mindustry [app] - real-time strategy, factory management, and tower defense game developed and published by Anuken
One Hour One Life - a survival massively multiplayer online game developed and published by Jason Rohrer. Each player lives for, at most, 60 minutes in a large, persistent world, with each minute representing a year of life.
Friday Night Funkin - rhythm video game developed by The Funkin' Crew Inc. and released on Newgrounds in 2020
The Dungeons of Moria - computer game inspired by J. R. R. Tolkien's novel The Lord of the Rings. One of the first roguelikes, developed in 1983
FreeCiv - empire-building strategy game inspired by the history of human civilization
FreeChess - Play chess on the web for free
Space Station 13 - multiplayer sandbox simulation
0 A.D. - a real-time strategy video game by Wildfire Games. It is a historical war and economy game focusing on the years between 500 BC and 1 BC.
Bobball [app] - Jezzball clone
Anarch [app] - Suckless Doom clone
OpenTTDOpenTTD.org [website] - simulation game based upon Transport Tycoon Deluxe
Lexica [app] - timed word-finding game
Pinball [app] - Simple Pinball game with bold, minimalist vector design and atmospheric sounds
BlockDrop [app] - Tetris clone
Kumquats [app] - Scrabble Clone
FOSS Game Engines
GoDot - free, open‑source game engine
Solarus - free, open‑source lightweight 2D game engine
OpenSurge2D - free, open‑source lightweight 2D game engine
Emulators
RetroArch.com - RetroArch is a frontend for emulators, game engines and media players. Among other things, it enables you to run classic games on a wide range of computers and consoles
DuckStation.org - a PS1 Emulator
PPSSPP.org - a PSP Emulator
DeSmuME.org - an NDS Emulator
Dolphin-Emu.org - a Gamecube & Wii Emulator
Miracle - a Javascript Sega Master System emulator that runs totally inside your browser
JSNES.org - A JavaScript NES emulator that runs in the browser
Game Launchers
Tabletop Gaming
RollDiceWithFriends.com - Just type in a name and hit the button to make your own room where you can roll polyhedral dice. Your friends can join you by typing the same room name, or you can send them the link from the address bar.
Octgn.net - a virtual table top with an integrated player lobby and chat system that supports custom card and board games.
StartPlaying.Games - Tabletop RPGs Run by Professional & Volunteer Game Masters
DiceCloud.com - Auditable, real-time character tracking for Dungeons & Dragons 5th edition
Game Tools
fmhy.net/gaming-tools - free game tools directory
Controlloid - Turn your smartphone into a wireless gamepad
SystemRequirementsLab.org - Here is the answer to "Can I run this game on my computer?"
Moonlight-Stream.org - allows you to play your PC games on almost any device, whether you're in another room or miles away
OpenGameArt.org - free game art & assets
MyAbandonware.com - download video games from 1965 to 2014 for free
Other
OpenGameArt.org - free game art & assets
Native Linux Games Collection [software]
Game-Icons.net [website]
A growing collection of SVG icons aimed mostly at video games