Cydia SubstrateCydia Substrate (formerly called MobileSubstrate) is the de facto framework that allows 3rd-party developers to provide run-time patches (“Cydia Substrate extensions”) to system functions, similar to Application Enhancer on the OS X.
LogosLogos is a component of the Theos development suite that allows method hooking code to be written easily and clearly, using a set of special preprocessor directives such as hook, end, ctor, dtor, orig, log.
TheosTheos is a cross-platform suite of development tools for managing, developing, and deploying iOS software without the use of Xcode. It is an important tool for people building extensions (tweaks) for jailbroken iOS; most extension developers use Theos.
LogifyLogify is a utility that accepts a class header (.h file) as input and generates a MobileSubstrate extension (.xm file) which hooks all of that class's methods, printing log messages when they are called. This helps a hook developer see when certain methods are invoked during use. Comes with Theos.