Drew McCormack released an initial version of his new Core Data sync library this week. It is back-end agnostic (supporting any online file storage service, including iCloud) and has some interesting ideas in terms of conflict sync. It's early days but this is a promising entry into the sync framework arena.
JazzHands is a new keyframe animation library which has been extracted from the IFTTT iOS app during development. It could be used for any kind of animation but is designed around multi part scrolling introduction/tutorial views that have become common across many iOS apps. It's pretty simple to put an animation together and the results look great.
I have been doing some work with TextKit this week and it's definitely one of the more immediately useful APIs which were delivered with iOS 7. The only puzzling piece is the letterpress effect which seems like more of an iOS 6 thing. Anyway, if you haven't got to grips with it yet then Colin Eberhardt dives in and gives us a tour.
This is a Twitter account which sends out links to iOS and Objective-C Stack Overflow posts a few times a day. I have been following it for a couple of weeks now and it has thrown up several posts which have been interesting to read and it's not overwhelming in the amount of posts it makes per day. Recommended.