We also have a category for projects that are focussed more on abstract community resources / engagement. So if you e.g. want to do some maintenance of information on this platform, review / update some existing addons that you find useful, come up with use case concepts or even create new content to aggregate/collect useful information for other community members (i.e. in blog posts), then that may be the category for you.
I also want to point out that there is no restriction on the number of suggested ideas that you can add. Some project ideas may not attract other interested participants, so you may choose to drop (some of) your own suggestions and join a different team on the day of the hack-a-thon. We will definitely not force anyone to work alone on a project just because it was their idea