bit niche but as a big streetcomplete fan I should have tried SCEE much sooner. So for any Openstreetmap contributors still holding out, that's a small recommendation https://f-droid.org/packages/de.westnordost.streetcomplete.expert
Breezy Weather is so pretty! I didn't know we had such beautiful FOSS software out there https://f-droid.org/packages/org.breezyweather
WebLibre I'm just trying out still, but I love that someone is extending Firefox on mobile https://f-droid.org/packages/eu.weblibre.gecko
Germans might appreciate Bahn Vorhersage. It's not magic, it won't know when your train will actually be there, but it helps planning trips on unfamiliar routes by giving you a much better idea of how much buffer time to plan. I actually prefer the webapp version here: https://bahnvorhersage.de/ (shout-out to @AskewLord@piefed.social downthread ;) )
I recently rediscovered UsageDirect for seeing how much time I spend in different apps. It's not really focused on this "spend less time on your phone" thing (you're old enough to decide that for yourself), it just shows you data that Android already collects anyway — and I love data! https://f-droid.org/packages/godau.fynn.usagedirect
Most of these, I discovered via f-droid's new feed, so that's also a rec! Even the Bahnvorhersage website I found that way via their app ^^. I just love "more free stuff"! https://www.stickycomics.com/computer-update/ :)
Be sure you didn't miss @jtrek@startrek.website's Too Good To Go recommendation downthread. It's about as commercial and nonfoss as it gets, but the end result is cheap food that would otherwise have been thrown away (I sometimes ask the store people what happens with the rest, only rarely is there some partial collaboration with a food bank type of place). Used to simply be a website to match people and restaurants iirc when I used it in Finland; now it requires an american credit card and anti-fraud algorithms magic to get anything but... still worth it