Could be anything associated with the Fediverse, Lemmy, Mastodon, Pixelfed etc.
I use this userscript with Tampermonkey for a layout that’s closer to old.reddit. (Script not mine.)
Once you understand that federation is a process managed by each instance it is easier to navigate communities
Your account is on an instance (server) that will only see communities on other instances if someone on your instance has already subscribed to that community
If you joined a large instance you might already see a lot of communities in your feed that you can subscribe to, but you might be missing some that exist but won’t show up in the search
A solution is to use lemmyverse.net or a similar site. You set your home instance, then search for communities. It gives you links that open on your instance where you can subscribe to (or block) communities. You do this in a browser, and it immediately reflects in the apps
e: If you are coming from reddit and just want to know what communities align with a particular subreddit, you can use sub.rehab then search for the community on lemmyverse
Don’t join the biggest instance.
wefwef.app is a great alternative for those who are used to Apollo.
I saw someone mention Jerboa for those used to RIF, and after a couple hours of light use, I gotta say it is indeed pretty similar so far.
As someone who came from RIF I couldn’t stand Jerboa. It was just too unintuitive. I’m currently using Connect for Lemmy, but honestly I’m just waiting and hoping Sync for Lemmy is going to fill the void that RIF left. Sync for Reddit probably would’ve been my go to app if I hadn’t discovered RIF before.
Is wefwef iOS only?
Works on any mobile browser but it looks and behaves like an IOS app. It’s ok but takes getting used to when you are used to Android.