@kaupas24 I’ve found that the magazine search function in kbin works really well. It pulls up top kbin magazines by default. They seem to be sorted by user count. But if you type, say, ‘technology’, it will show all magazines/communities from kbin and Lemmy that are technology oriented. You can also type ‘@beehaw.org’ to view all communities on the Beehaw instance.

For Lemmy we have https://browse.feddit.de/ This partially solves what you want i think.