Tools, yes, instances, no, but there are Lemmy explorer (https://lemmyverse.net/) which you can search for both instances and communities.

Not yet but I’m open to suggestions!

My home feed is all communities, I then block communities continously that I don’t want to see, if Lemmy had more active users I would probably work more with subscriptions

deleted by creator

No, but that’s not a bad idea

I’ve got 3 user accounts on 3 separate instances that I have loaded in Boost. So switching between them is effectively like a bookmark between the three.

Even though I’m subbed to roughly the same communities I’ve noticed what gets shown is quite different.