http://sourceforge.net/projects/machoview/
https://github.com/gdbinit/MachOView
http://www.newosxbook.com/files/jtool.tar
Command Line Tool for interacting with MachO binaries on OSX/iOS
https://github.com/alexzielenski/optool
Visual Mach-O binary parser
https://github.com/samdmarshall/MachOParse
PHP script for modifying Mach-O executable i386 and x86_64 files.
https://github.com/TheFox/macho
Portable libraries and utilities that manipulate HFS+ volumes and Apple's DMG images
https://github.com/planetbeing/libdmg-hfsplus
checkipa scans an IPA file and parses its Info.plist (in Payload directory) and embedded.mobileprovision files. It performs checks of expected key/value relationships and reports the results.
https://github.com/apperian/iOS-checkIPA
codesignature construct
A Mach-O binary codesign remover.
https://github.com/x43x61x69/codeunsign
iReSign allows iDevice app bundles (.ipa) files to be signed or resigned with a digital certificate from Apple for distribution. This tool is aimed at enterprises users, for enterprise deployment, when the person signing the app is different than the person(s) developing it.
https://github.com/maciekish/iReSign
http://www.newosxbook.com/files/hfsleuth.tar
Generate Objective-C headers from Mach-O files.
https://github.com/nygard/class-dump
The Mach-O disassembler. Now 64bit and Xcode 6 compatible.
https://github.com/x43x61x69/otx
http://code.google.com/p/networkpx/wiki/class_dump_z
http://www.hex-rays.com/products/ida/index.shtml
Collection of idapython scripts for dealing with the iOS kernelcache
https://github.com/stefanesser/IDA-IOS-Toolkit
Simplifies working with Objective-C binaries in IDA Pro
https://github.com/zynamics/objc-helper-plugin-ida
http://www.hex-rays.com/products/ida/index.shtml
Patch PE, ELF, Mach-O binaries with shellcode