They were reasonably popular on reddit, 3m+ and 2m+ subscribers respectively. I started posting once per day to each of them soon after I migrated over, though my meme stash has mostly run dry at this point (I do have a bit more to post to anime_irl). There are some regular posters in anime_irl now, but animemes has been pretty dead since I stopped posting. I've also promoted them in the usual places.
There's also my own community, kbin.social/m/specialized_instances / /c/[email protected], for cataloging topic/location focused instances. It works fine as a solo project, but I wouldn't mind having more suggestions of things to add to the list.