These are some common libraries I use in my code.
All C libraries are vb6 compatiable (stdcall)

pe_lib   - vb6 ActiveX DLL
           PE file format parsing code

proc_lib - vb6 ActiveX DLL
           Process Enumeration/Manipulation

globals  - vb6 Activex DLL
           Global Multiuse class with common lib functions

olly_dll - C DLL  
           ASM/DISASM engine 
           GPL Copyright (C) 2001 Oleh Yuschuk

hooklib  - C DLL
	   Detours style hooking engine 
           extended version of Daniel Pistelli's ntcore.com hook engine

zlib     - C DLL
           ZLIB compression library - win2k+ compatiable
           Jean-loup Gailly & Mark Adler