Rubberduck
Every programmer needs a rubberduck. COM add-in for the VBA & VB6 IDE
...Avoid common pitfalls (some not-so-common) with dozens (100+) of configurable inspections. Gain full control over module and member attributes, create a virtual folder hierarchy, and document modules and procedures, all with special comment annotations. Navigate a Classic-VB project like never before, quickly locating identifier references, interface implementations, and anything else that has a name. Add a full folder structure for organizing your modules. Write code that runs your code and verifies its output is as expected, given controlled inputs. ...