I’d like some kind of avatar generation method that actually looks good. MonsterID gets there, but isn’t really appropriate for most applications.

https://robohash.org/Aeolun looks good imo

Also see this http://avatars.adorable.io/

I once had issues with caching js resources, while I was developing, so I wrote some code to MD5 hash the js, generate an identicon from the MD5 hash and then output the identicon and hash with the name of the js file on the browser's console so I could quickly verify that the file had changed and been loaded in the browser when I refreshed the page.

I like the idea of using identicons for build hashes! Might have to start doing that myself.