Librera Reader is a customizable and feature-rich app on F-Droid for reading books and other media. Its supported file formats are PDF, EPUB, MOBI, DjVu, FB2, TXT, RTF, AZW, AZW3, HTML, CBZ (comic) and CBR (comic). It's pro version is available for free on F-Droid.
Pair this app with another app like Quicknovel (do you want a review on that? Let me know on my Mastodon account) and reading books becomes very easy and free. You can also read comics in CBZ and CBR formats.
Key Mapper is an app on F-Droid to map hardware buttons on your device to many different actions like turning on and off your flashlight, calling someone, opening an app etc. There are many actions that can be triggered, far too many to list here. So i'll just imclude some screenshots of some of the actions.
Cloudstream 3 is a FOSS (free and open source software) app on F-Droid for streaming movies, tv shows and anime. It uses different providers to get media. New providers are added all the time. It’s the successor to Cloudstream 2, which is no longer supported. It also supports Android TV .(it’s better than all those other sketchy apps like cinehub imo)