Xcode plug-ins
With this plug-in, don't have to hard-code UIColor by colorWithRed: green: blue: alpha: method again.
Plugin for Xcode to make working with colors more visual
With this plug-in, don't have to con over every image resource's name.
Xcode plug-in that provides autocomplete for imageNamed: calls
Vi mode for Xcode, improve your coding efficiency.
Xcode plugin for Vim keybindings http://programming.jugglershu.net/softwares/xvim.html
Scripts
perl sort-Xcode-project-file MyApp.xcodeproj/project.pbxproj
Unit testing
xctool is a replacement for Apple's xcodebuild that makes it easier to build and test iOS and Mac projects.