I made a comprehensive list of NIPs to try and shed light on a few questions:
What's the next free NIP number? 17 if you don't count PRs. 62 if you do.
How many NIPs have been created? 132
How many NIP number collisions are there? 39.
How many do you need to worry about to "create a client in a weekend?" Still unanswered.
Can I do anything nerdier than read protocols? Answer yes.
https://codeberg.org/nostr/nip-index/src/branch/main/README.md