If you're looking for interesting accounts to follow on Mastodon and the Fediverse, you might find this a useful starting point:

➡️ https://fedi.directory

It's not intended to list everyone, it's just meant to give a few good starting points on particular topics. Once you follow one person on a topic, you'll discover even more relevant people through posts they share.

There's also an accompanying account:

➡️ @FediFollows

I run the site and account, so if you have any questions ask me :)