They say time is is the most valuable resources. Right now, time feels quicker for me these days and I often lose track of it.
Because of that the app should have the same purposes as an old clock, it plays a little “ding” or a notification every 15 minutes, 30 minutes, or 1 hour, or as long as I like.
Preferably installable with f-droid, can I have an app recommendation.
This sounds basic enough that you’d almost certainly be able to do this with Tasker. It’s not FOSS though (and a paid app).