Ah, Spring is a Nostr-centric browser that doubles as a signing extension; it's mainly backed by Nostr.Band and works well from my time using it.

Considering I'm using Amber now, that purpose is now redundant for me as I can use Calyx Chromium with my go-to Nostr apps. Good for discovery though, since there are some services I didn't know existed until Spring revealed them to me.

I also have the Primal client on my phone, but don't use it much as it was lacking in feature set compared to Amethyst. Now it has the one thing it doesn't currently: stability.