I think highlighter.com and YakiHonne.com are interesting for a blog posting medium type app, coracle.social has the new encrypted private group stuff which is exciting. 

There’s a subjective wiki which nostr:npub1l2vyh47mk2p0qlsku7hg0vn29faehy9hy34ygaclpn66ukqp3afqutajft is working on which is also interesting.

Here’s a good list of the apps: https://www.nostrapps.com