Personally, I like to micromap. I’ve mapped individual trees, poles, benches, and trashcans, for example. I also like to map forested/scrub areas. Buildings themselves are also kind of fun to map, so long as I have the building plugin installed to JOSM.
Fair warning that Carto seemingly tends to update about twice a year and that this was merged maybe a couple weeks after an update. So you’ll be waiting for it to show up…
… but it will show up.