RMG v0.1.9 is released. Rosalie's Mupen GUI is a free and open-source mupen64plus GUI written in C++. It offers a simple-to-use user interface.

RMG changelog:
Add -f/--fullscreen commandline argument
Add Automatically Switch To Fullscreen On Emulation Start option to settings -> Interface
Add support for unicode in ROM file paths on windows (this already worked on linux)
Add support for Advanced Homebrew ROM Header save type (mupen64plus/mupen64plus-core#977)
Remove Overclock Factor from the core tab (it's still in the game core tab)
Fix save type being wrong when changing per-game core settings

Download: RMG v0.1.9
Source:Here