When I set up mine, I created a separate /data mount point and drive for anything that I expect to keep between distros. The problem with keeping the home directory is that means all your personalized config files which may or may not apply to a new distro you switch to. I keep configs I want to keep in a git repo (like my i3 configs and scripts that I absolutely wouldn’t want to redo from scratch), data I want to keep in /data, and everything else can pretty much be wiped for a new distro on a whim without too much hassle.
I haven’t tried these so I cannot comment on their quality. But this has a list. Of particular note is RetroArch, OpenEMU, and Gens as three FOSS options.
Edit: Also, alternativeto.net is usually a decent source for finding alternatives for specific software. Here’s the list for Kega Fusion alternatives. This has some more options than the other link I provided.