iCanHazShortcut - Simple shortcut manager for OS X 10.8 or higher.
Keyclone - Keyclone is a key broadcasting application that allows users to control multiple instances of an application using a single keyboard/input device. While commonly used for m...
CustomShortcuts - Customize your Mac menu keyboard shortcuts for free.
ISBoxer - Play characters together. Powerlevel yourself. Multibox.
Keysmith - Create custom keyboard shortcuts for your Mac and the web
HotkeyNet - HotkeyNet is free multiboxing software.