Some interesting Nostr links I have bookmarked recently:

https://nostrstuff.com/ - Open source web app that can do things such as query info about nostr relays.

https://nostrcheck.me/ - Media hosting, NIP-05 provider.

https://nips.be/ - Short urls for NIPs e.g. https://nips.be/57 for the NIP that defines Zaps

https://bountsr.org/ - Nostr bounties

https://relay.exchange/ - List of paid relays