MaterialDesignInXamlToolki Google Material Design style control library
Address: https://github.com/ButchersBoy/MaterialDesignInXamlToolkit
MahApps.Metro Metro style UI library
Address: https://github.com/MahApps/MahApps.Metro
There is also a related icon library: https://github.com/MahApps/MahApps.Metro.IconPacks
Fluent.Ribbon imitates Office style
https://github.com/fluentribbon/Fluent.Ribbon
SharpDevelop C# editor
https://github.com/icsharpcode/SharpDevelop
ControlzEx can be dragged
https://github.com/ControlzEx/ControlzEx
Dragdrop
https://github.com/punker76/gong-wpf-dragdrop