Okay, found this, maybe of interest:
"Trunk allows you to mass-follow a bunch of people in order to get started with Mastodon or any other platform on the Fediverse".
There's also a list of Organizations.
I'd be surprised if it's going to be fully up-to-date any time soon, given the ongoing mass migration from 'the other place' and media coverage generating curiosity.
A newer server operated by the Mastodon gGmbH non-profit