EmuNations

Cemu is an open source emulator for WiiU which is considered to be in experimental state. That said, it's able to play quite a few number of games very smoothly without major issues and graphics packs can even be injected into games. Please check compatibility list for more details.

Extensions:

   Cemuhook

• GamePad input source override for cemu, including full motion sensing support (requires additional software, see the guide)

• Adds code/data patching to your games at load-time, which you can activate and share the same way you do graphic packs!

• Think of it like a pcsx2 plugin, implementing something not in the core

   Cemu Graphics Pack

• Community Graphic Packs which is used to upscale and change your Wii U games

   BetterJoy

• Allows the Nintendo Switch Pro Controller, Joycons and SNES controller to be used with the Cemu Emulator and System-Wide

Decaf is an open-source Wii U emulator recognized as the very first Wii U emulator ever released. It's currently in the early stages of development but can successfully boot several commercial games, albeit slowly with many glitches.