When I started out learning iOS application development I wished that there was a list of libraries that were proven to work well, were well documented and had great coverage on Stack Overflow.
Here is the list of libraries and frameworks I use with great success in my projects:
ASIHTTPRequest — A perfectly decent library for all of your HTTP requests including downloading the content of a URL or submitting a form to a website API/endpoint. (Alternatives: GTM HTTP Fetcher thanks @neilang)
SBJSON — A great JSON parser and generator. Turn JSON into NSDictionary’s NSArrays (etc) and vice versa.
Apple’s Reachability class — Included in ASIHTTPRequest, but worth a mention. Apple provides a class for detecting whether you have 3G/Edge access and the device is capable of routing IP traffic. It also pings Apple’s servers to check if you have “greater internet” availability.
EGOImageView — If you are working on a web-based app and you need to show a tableview full of web-loaded images you will want a library like this.
MBProgressHUD — A fairly easy to implement class for showing a translucent HUD (Heads Up Display). Use this if you want to notify a user that an operation has completed or the progress of some database operations that are running.
SFHFKeychainUtils — Fairly straightforward class for interacting with iOS’ keychain. If you are storing user’s passwords in NSUserDefaults – stop. Use the keychain and give this class a go.
MOC/NSManagedObject+Additions — Custom proprietary class for handling core data interaction. Written by @abhibeckert with additions from yours truly. If you are using or have written a very light weight Core Data wrapper, let me know in the comments.
If you have tried any of these and have found an alternative that works better let me know in the comments.