​​AxTools​​ AxTools is a company that makes addins for VB6, and lately, VS.NET. Basically, their piece de resistance is the most wonderful CodeSMART, which is the most amazing IDE enhancer for VB6 I ever had the pleasure of using. Do I sound gushy? I use it every single day and I wouldn't know what to do without it. The Project Explorer alone would justify the price, and it has tons and tons of features besides that. AxTools also makes Source+ (among other things), which is a kind of cool code repository (also integrated with VB, and if you want, with Office/VBA). I haven't tried CodeSMART for .NET, but if it's anything like their VB6 product, it's worth every penny.

​​​MZTools​​​ MZTools is another great add-in for VB6. Although CodeSMART (see above) does just about anything I need it to, MZTools has some neat features like Procedure Callers and an XML documentation generator that just plain rocks. It's a good addition to CodeSMART, and best of all, it's free.

​​​VBAdvance​​ What VBAdvance does should be in the project properties dialog in VB. It essentially inserts itself in the VB build process and plays around with the linker, allowing you to create normal exports from VB DLLs (i.e., you can implement a RunDLL32 entry point), build resource-only DLLs and much more. Very cool - and it's the first add-in of this type that I've tried which actually works.