When you first launched Minetest, didn't you think it was just Minecraft? Actually not. Although their interface, style, and gameplay are almost the same, Minetest is essentially a free, open-source and cross-platform voxel game engine (written in C++ and Lua, using the Irrlicht Engine). It was created by Perttu Ahola and first released in 2010, and is now developed by a team of volunteers, with significant contributions from the community. It's available for Linux-based systems, FreeBSD, Windows, Mac, and Android platforms, and provides an API for users to create their own games and mods written in Lua.

xemu is a free, open-source, and cross-platform Xbox emulator made by Matt Borgerson, continuing much of the work done on XQEMU. It emulates the hardware of the original Xbox game console of Microsoft, allows users to play their Xbox games on Windows, Mac and Linux platforms.

Krita (formerly called KImageShop, Krayon) is a free, open-source and cross-platform digital painting software developed by Krita Foundation (part of the KDE Community) from Sweden. It is fully functional, capable of the entire painting process from drafting, lining, coloring to post-adjustment; can draw concept sketch, illustration, cartoon, animation, scene and 3D mapping; supports digital board, pressure sensing, anti-shake, layers, filters, color management, and other functions.

TeamTalk is a free and open-source multi-user conferencing system for Windows, Mac, Linux and mobile platforms, developed by Bjoern D. Rasmussen from Denmark. It allows user to perform real-time voice and video communication through Internet. For voice encoding, it uses the Opus and Speex audio codecs; for video streaming, it uses the WebM video codec.

MuseScore is a free, open-source and cross-platform music composition and notation software, widely used by schools, conservatories, choirs, orchestras around the world. It is specially designed to provide a high performance-to-price ratio of alternative to the professional music score making software, such as Sibelius and Finale, and to became the world's most popular notation software.