https://github.com/Atmosphere-NX/Atmosphere/
https://old.reddit.com/r/emulation/comments/hygtnx/mesospher...
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(also, one more particularly cool application made possible through homebrew is game streaming - from a desktop pc or other device.)
Animal Crossing and all four (technically two but you know) Pokemon games have no cloud save support at all, arguably all games for which players would absolutely want cloud saves. On top of this is a pretty long list of third-party titles.
Also you can get a second hand ps4 pretty cheap nowadays relative to it's hardware and power consumption - could make a decent home server if you chucked some variety of linux on there (is there much support for the hardware?)