Bookmarking this to refer back to later, but here are the ones I use all the time:

Web Clients
- Nostrudel
- Primal
- Coracle
- Snort

Specific Content
- Zap.Stream
- Wavlake
- Flare? (Haven't checked it out much yet, but looks good)

Tools
- Advanced Nostr Search
- Shipyard
- Highlighter
- Listr

I know there are way more that I need to try out. Flockstr comes to mind and NsecBunker, though I never could get it to work for me.