GMap.NET is great and Powerful, Free, cross platform, open source .NET control. Enable use routing, geocoding and maps from Google, Yahoo!, Bing, OpenStreetMap, ArcGIS, Pergo, SigPac, Yandex, Mapy.cz in Windows Forms & Presentation, supports caching and runs on windows mobile!

MDIWindowManager is a control that allows you to create MDI applications using a modern Tabbed Document Interface. The control works on traditional MDI forms and does not require that children be derived from some proprietary base class or implement some special interface or framework. The goal of MDIWindowManager was complete transparency and absolute ease of use all while supporting advanced features such as tiling.

Mini SQL Query is a minimalist SQL query tool for multiple databases is now on GitHub: https://github.com/paulkohler/minisqlquery