these are some I tried after getting started with Iris a couple months ago:

nostr.rocks (good ol' branle)

nostrudel.ninja (swiss knife of nostr)

satellite.earth (cute UI, plus it shows existing nostr communities)

nosta.me

nostree.me (these two for short, nice-looking user cards)

slidestr.net (nostr's imgur)

flare.pub (nostr's youtube)

yakihonne.com (nostr's substack)

coracle.social (I haven't checked this one yet 🧐)