Hi!
In the Apollo app (basically the reason i started using reddit and the reason i also left reddit lol) there was a very useful feature: friends.
It was not a mutual friendlist like facebook, and not even much of a follow like twitter; it was more a ‘‘favorite users’’ list.
Basically I added in there people that always commented stuff I was interested in and this helped me find new communities and interesting post without relying on other discovery ways. Seen the decentralized nature of lemmy, i think it could be even more useful than on reddit.
Given that you can add Lemmy users in Mastodon / Friendica I think you can follow them from an account on any of those. Lets see as I follow my Lemmy account on friendica.