Well, actually, PieFed.social has enabled it’s API which means that the app Interstellar can be used with it. Find out more about the app at https://interstellar.jwr.one/. iOS users can use the testing version at https://testflight.apple.com/join/JXRtHye2
https://feddit.online, another PF instance, has enabled the API too and I expect others will follow in good time.
Well, it can federate with lemmy instances and there are way, way more lemmy users/communities than there are piefed user/communities. If you want to see the local communities on a piefed instances, it would be at
/communities/local. This is the page for piefed.social.