Three20 is an Objective-C library for iPhone developers

Display and interact with SVG Images on iOS / OS X, using native rendering (CoreAnimation)

Chameleon is a port of Apple's UIKit for iOS (and some minimal related frameworks) to Mac OS X.

Official frugal and native macOS Syncthing application bundle

Drop in sharing features for all iPhone and iPad apps

Chart library for iOS

Unofficial core-plot mirror (official version now here: https://github.com/core-plot/core-plot)

CoreSync is an elegant Objective-C diff/patch library for JSON and NSDictionaries.

elegant cocoa XML marshalling with a small memory footprint

A crash reporting framework for macOS

Customizable inspector windows for Cocoa