RMG v0.3.1 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:
Fix taking a screenshot not working in some cases (see mupen64plus/mupen64plus-core#992)
Fix some games being unable to save due to having an illegal character in the save filename (see mupen64plus/mupen64plus-core#993)
Fix OSD tab crash in GLideN64 (see gonetz/GLideN64#2752)
Fix an issue where the graphics plugin would show the 64DD IPL as ROM name in the settings even after booting a cartridge
Fix "Refresh ROM List" in Hotkeys tab in settings dialog not reverting back to defaults when clicking on 'restore defaults'
Fix "Remove Duplicate Keybindings" in settings dialog not behaving correctly in some cases
Fix fallback application icons not respecting system icon theme on linux
Add support for ndd/d64 files in zip files
Add support for using the basename of the ROM filename for covers
Add support for binding multiple inputs in RMG-Input
Improve behavior of window when launching RMG with a ROM using the commandline
Improve behavior of error message when emulation fails
Improve behavior of hotkey buttons in settings dialog

Download: RMG v0.3.1
Source:Here