2D
Orx
Orx is an open source, portable, lightweight, plugin-based, data-driven and extremely easy to use 2D-oriented game engine.
Pygame
Pygame is a set of Python modules designed for writing games.
Moonlighter
(1 Mar 2017)Moonlighter is a Action RPG with rogue-lite elements about Will, an adventurous shopkeeper, that secretly dreams of becoming a hero.
Genre: Construction and management, Adventure, Action 
Aveyond 2 : Ean's Quest
by Aveyond Studios and RadialApps
1.0.0
(4 Jun 2016)
Enjoy the classic RPG on Linux
Snow has fallen on a magical vale where it has never snowed before.
Genre: Text Based / Visual Novel, Role-playing 
Aveyond 1 Rhen's Quest
by Aveyond Studios and RadialApps
1.0.0
(2 Jun 2016)
Fight monsters and explore a medieval world.
Genre: Text Based / Visual Novel, Role-playing 
Defect
(1 Dec 2015)Create the most powerful ship in the galaxy piece by piece, then lose it to your traitorous crew.
Genre: Strategy, Action 
Source of Tales
This game initially started as our entry for the Liberated Pixel Cup 2012.
Genre: MMO, Role-playing 
Chaos Projectile
Chaos Projectile is an open source 2-dimensional action arcade game with role-playing elements, currently in development.
Genre: Arcade, Beat 'Em Up, Action 
Turres Monacorum
A scifi tower defense made with löve2d and lua.
Genre: Construction and management, Strategy 
JCloisterZone
JCloisterZone is a Java implementation of a popular board game Carcassonne.
Genre: Boardgame, Strategy