Most popular apps
Steam
Steam is a digital distribution, digital rights management, multiplayer and communications platform developed by Valve Corporation. It is used to distribute a wide range of games and related media entirely over the internet, stretching from one-man independent efforts to some of...
itch.io
An online game marketplace and community. Also an app which manages downloading and updating of games acquired through the website.
Lutris
Lutris is an open source gaming platform for GNU/Linux. It allows you to gather and manage (install, configure and launch) all your games acquired from any source, in a single interface.

RetroArch
RetroArch is a graphical frontend for emulators, game engines, and media players.
Heroic Games Launcher
Heroic is an Open Source Game Launcher for Linux, Windows and macOS (10.15+, won't work properly on High sierra and older versions). Right now it supports launching games from the .

Proton
Proton is a tool for use with the Steam client which allows games which are exclusive to Windows to run on Linux kernel operating system. It uses Wine to facilitate this.

GOG GALAXY
Connect GOG GALAXY 2.0 with multiple platforms and unite all your games and friends scattered across them in one powerful app.
Dolphin Emulator
Dolphin is an emulator for two recent Nintendo video game consoles: the GameCube and the Wii. It allows PC gamers to enjoy games for these two consoles in full HD (1080p) with several enhancements: compatibility with all PC controllers, turbo speed, networked multiplayer, and...