These are thrown together. I use them on my own internal projects so when I have a free moment, I put a little bit together. It's not extensive.
Typing #import will trigger a look up of all .h files in the working
directory of the file referenced. This works for most projects, but could
probably be expanded.
Typing - (<char>) will look up the header for the current .m filename and offer
auto-fills for the methods declared in the header.
Responses will be in snippet format so you can tab through the options.
Try mixing with https://github.com/echoldman/Sublime-Text-Objective-C-Snippets for extra helpfulness.