Just stumbled across IzzyOnDroid, an F-Droid compatible repository of FOSS software. The repo currently holds 226 apps, not all of which seem to be on F-Droid.
While it is similar to F-Droid in being a repo of FOSS apps, they don’t build its own APKs but host those provided by the maintainers themselves. However, their list of apps could be interesting to F-Droid, as they might have some apps which are not on F-Droid yet.
Is there a way to quickly diff two F-Droid repos (apps available in one but not in the other)? Then I’ll take a look and report back.