Found out you can sideload stuff onto roku, what do I put on it?

I have a few cheap Roku tvs, turns out they have developer mode and you can sideload stuff onto it. Unfortunately, DDG just gives me a bunch of guides on how to activate developer mode, each one ending with "go find it yourself on github" when it comes to what to actually put on it.

Anyone have experience doing this? Do you have suggestions for what to load on it? We only really use it for jellyfin at the moment but this feels like a fun little thing to play with.