While technically not a fully Federated app, Aether is one of the best decentralized Reddit alternatives next to Lemmy. Same as Lemmy, user base is a current issue. But the app is
Lemmy: A Decentralized Open-Source Reddit Alternative To Explore
Kbin.social is an easy to onboard Lemmy instance/Reddit alternative in the fediverse (unsponsored recommendation) : r/RedditAlternatives
Petition for mods to sticky Reddit alternatives (Lemmy, Kbin, etc) on their subs/comments : r/ModCoord
Looks like this might be a thing now!
The Lemmyverse ain't all it's cracked up to be : r/RedditAlternatives
Lemmy: A Decentralized Open-Source Reddit Alternative To Explore
Lemmy and Kbin: The Best Reddit Alternatives?
Which Reddit alternative? Aether vs Kbin vs Lemmy vs Saidlt : r/privacy
Reddit alternative Lemmy is decentralized and free to self-host : r/videos
Reddit alternative Lemmy is decentralized and free to self-host : r/videos
Just downloaded Memmy for Lemmy and the interface is definitely inspired by Apollo. Getting the feel for Lemmy already! : r/apolloapp
Lemmy and Kbin: The Best Reddit Alternatives?, by PCMag, PC Magazine
For those using Lemmy & Kbin: Instance Assistant v1.2.4 is here! : r/Mastodon