It's also basically the /r/startrek community. One of the earliest to migrate, and migrate wholesale.
Course I'm not sure how smart each topic having its own instance is going to be. Feels like that just means the mods you knew from Reddit are now admins of their own neighborhood, answerable to no one, and that could be a good thing...but I can see a lot of ways that creates issues in the future.
Bias is I was a mod, but I figure the people both technically literate enough to host an instance and that actually did leave reddit when push came to shove are the good ones, generally. Most of the shitty mods haven't left precisely because it would mean giving up what little power they have.
They have a bunch of communities and users, but they are all incel/transphobia themed. They have communities like !realmen@exploding-heads.com (andrew tate rhetoric) and !dankmemes@exploding-heads.com (transphobia). Block them if you value your sanity.
I took a look through exploding-heads and lemmygrad recently, just to see what they were like for myself. Lemmygrad was about what I was expecting. EH on the other hand was just kind of... sad? Pathetic? The one admin begging people to participate more was particularly so.
Not sure I understand the question, but you should be able to subscribe to their communities (such as !moviesandtv) from wherever you are posting from. :)
lemmit.online is an instance that is entirely made up of reddit cross-posts. It has one account, a bot, that copies every post made to any subreddits on its list so you can see the content without going to reddit.
There are some with very specific purposes/nationalities (like lemmynsfw, lemmy.ca, and one Portuguese-only one for people from Portugal) that somewhat resemble the porn subs and the country-themed subreddits like r/canada and r/suddenlycaralho respectively.