PICO-8 - Lua-based fantasy console for making and playing tiny, computer games and programs.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
Moai - Moai is a spiritual successor to one of the elder gods of pixel editing: Autodesk Animator.
Unreal Engine - Unreal Engine 4 is a suite of integrated tools for game developers to design and build games, simulations, and visualizations.
GnuPG - GnuPG is a complete and free implementation of the OpenPGP standard as defined by RFC4880 (also known as PGP).
Unity - The multiplatform game creation tools for everyone.