Telerik® JustCode™ can auto-complete any referenced type and automatically add the required usings.
Supported: C#, VB.NET
How to complete all types
Similar to Visual Studio's intellisense - use Ctrl+Alt+Space on a word you want to auto-complete. Telerik® JustCode™ will show you a list of all types that are referenced somewhere in you solution, not just the current project, and auto-navigate you to the one that matches best, press Enter and you're done - all needed usings and references will be added automatically.