Yes.

A. F-Droid only allows completely open souce stuff and informs you about things like whether it has privacy concerning features like trackers, relies on connecting to a closed source server, etc.

B. Obtainium doesn't give you any of those guarantees, but you can pull from a lot of different locations including .APKs from Microsoft GitHub releases, and

C. Aurora only allows you to get things listed on Google's play store (same backend)

Two are. Obtanium just reads the github repositories periodically for updates then let's you decide when to update. It's very useful.