The classic answer is: "please write all this boring documentation stuff for $your_favourite_project", or pick a boring bug report in some project, triage ot and fix it. It's all very valuable stuff, but it's fracking boring.

The real answer is: find a project you like, even a small one, and patch it to do something you find even more useful. If you think you can't do it, maybe it's a good chance to use it as a skill-up project. Or, rewrite an interesting lib or useful tool from $language_you_dont_like to $language_you_love. Or just put on GitHub some private tool you wrote that someone else might find useful.