Decaf

Decaf is an open source Nintendo Wii U emulator and an alternative to the more established Cemu.

Decaf does not yet emulate the Wii U as well as Cemu, but it has made steady progress towards running commercial games.

Decaf was originally a Windows 10-only emulator because it relied on DirectX 12. Its lead developer, exjam, later dropped DirectX 12 in favour of OpenGL 4.5, which allowed Decaf to run on other platforms, and it has since gained a Vulkan renderer.

Decaf can run some commercial Wii U games, but you are likely to run into graphical glitches and serious bugs. It is still very much experimental, and for playing Wii U games Cemu is the more practical choice.