Deleaker - Deleaker finds memory leaks, GDI leaks, leaks of handles, USER objects and others. Available both as a Visual C++ extension and standalone application.

EasyHook - The reinvention of Windows API Hooking

Relyze WonderLeak - WonderLeak is a native Windows allocation profiler, designed from the ground up to be blazingly fast and handle profiling large multi threaded applications with ease.

Deviare API Hook - Deviare is a professional open source hooking engine for instrumenting arbitrary Win32 functions, COM objects, and functions which symbols are located in program databases (PDBs).

GlowCode - C++ and other programming languages profiler

madCodeHook - "madCodeHook" offers everything you need to hook code (mostly APIs).