Other people got a lot of the ones I was going to mention, but there's also NewPipe, Orbot, TorBrowser, Markor, Amethyst, Element, SignalFOSS, and BlueWallet.

Some of them require adding additional F-Droid repos (SignalFOSS for sure since they're blocked from the main repo, and possibly others), but they are all available via F-Droid.