Some clients (like nostrudel for desktop/web and Amethyst for Android) make a good job at showing clear separation for different kinds (Public Inbox, DMs, Private Relays, Search realys, etc).

As for a list of top relays, that's probably gonna be a matter of trial and error.

P.S. For general use I go with nostr.wine, relay.primal.net and relay.damus.io. For DMs, inbox.nostr.wine. On Android I also use Citrine as a local relay.