Unity - The multiplatform game creation tools for everyone.
GetBadges - GetBadges is a gamification platform which allows developers to play and compete while using software development tools.
Godot Engine - Feature-packed 2D and 3D open source game engine.
HabitScript - Gamify your coding time
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
Goals & Challenges by Fini - A social way to gamify goals and habits with challenges