[boricj]

One simply doesn't find a side project.

If nothing else side projects consume time, so it must be able to hold your attention and focus. Therefore, it must be interesting in some way for you personally, otherwise you're just going to shelve it immediately.

As an example, the last side project I've worked on was a decompilation/reverse-engineering of a PlayStation game. I was inspired by existing projects such as Super Mario 64 decomp and REDRIVER2, so I picked a game of my childhood and started hacking. This somehow snowballed into stumbling upon an entire, seemingly unexplored field of software engineering (delinking), which I've leveraged to do many acts of outright heresy in the name of science. To me, this topic is like a hardcore puzzle, one that is intellectually rewarding to solve (plus, I get to melt the brains of any software developer I meet with it).

The point is, while a side project can be a lot of work, it isn't actually work. You're doing it not because you get paid for it, but because you want to. Find something that scratches your own itch.