a few examples of what I mean:
https://buddypress.org/community/groups/post-rich-videos-and-photos-galleries/home/ – does not integrate at all with BP
https://buddypress.org/community/groups/login-with-ajax/ – not a BP plugin, just compatible. um, who cares
https://buddypress.org/community/groups/default-blog-options/ – nothing to do with BP
https://buddypress.org/community/groups/bannerman/ – nothing to do with BP
and that was just the top of the first page.