[saratogacx]

It isn't an invite only club. Anyone can submit an existing application[0] and an app author can provide a metadata pack to speed up the process. They have some requirements to accept but it isn't a situation where a developer is just waiting around for the letter of invite to arrive[1].

[0] https://f-droid.org/en/contribute/ [1] https://f-droid.org/en/docs/Submitting_to_F-Droid_Quick_Star...

[heavyset_go]

You can also use other repos than F-Droid's if you want to get apps from elsewhere.

[AlienRobot]

But it's an open-source only club, that severely limits the sort of developer that can have their application published in that store at all.