Kega Fusion is a Sega game system emulator. It can handle games from Sega 8 bit, 16 bit, and end even one 32 bit console.
It is closed source but the binary is free to download and share.
It relies on 32 bit architecture so it doesn’t work on Ubuntu anymore after Ubuntu switched to 64 bit.
As far as I know it is no longer being developed by the developer.
There is a flatpak for it but no appimage and no snap. This kind of legacy app which relies of older libraries that is still more functional than any of the opensource projects trying to do the same thing seems like the kind of thing snap would be perfect for.