Actually, F-Droid has quite strict requirements on the apps it will accept, and it enforces them.
Low-effort spammy apps with ads and in-app purchases are unlikely to be accepted.
Standard Android in-app purchases, efficient notifications, or ads which use Google services, won't be accepted at all, though FLOSS versions of those things are ok in principle.
> All applications in the repository must be Free, Libre and Open Source Software (FLOSS) – for example, released under a GPL or Apache license.
> Every effort is made to verify that this is actually the case, both by visual inspection of the source, and by building the application from the published source.
> We cannot build apps using Google’s proprietary “Play Services”.
> We cannot build apps using proprietary tracking/analytic dependencies like Crashlytics and Firebase.
> We cannot build apps using proprietary ad libraries.
> The source code for the application must be maintained in a publicly accessible Version Control System which we have support for
> The original app author has been notified (and does not oppose the inclusion).
Low-effort spammy apps with ads and in-app purchases are unlikely to be accepted.
Standard Android in-app purchases, efficient notifications, or ads which use Google services, won't be accepted at all, though FLOSS versions of those things are ok in principle.
From https://f-droid.org/docs/Inclusion_Policy/ :
> All applications in the repository must be Free, Libre and Open Source Software (FLOSS) – for example, released under a GPL or Apache license.
> Every effort is made to verify that this is actually the case, both by visual inspection of the source, and by building the application from the published source.
> We cannot build apps using Google’s proprietary “Play Services”.
> We cannot build apps using proprietary tracking/analytic dependencies like Crashlytics and Firebase.
> We cannot build apps using proprietary ad libraries.
> The source code for the application must be maintained in a publicly accessible Version Control System which we have support for
> The original app author has been notified (and does not oppose the inclusion).