Breezy weather, cause goddamn is it nice to have an actually good weather app that doesn't want the most bullshit permissions that a weather app shouldn't ever need access to.
Image Toolbox - it's pretty nice.
Cool Reader - dead project, it's successor KnownReader isn't on F-droid, but it doesn't matter much. I still haven't gotten completely used to known, cool works perfectly fine and it has been my e-reader of choice ever since the j2me days.