Sylapse 

An MvvmLight helper for calling RaisePropertyChanged on the UI thread from a PCL. See Project Site for instructions.

Text input anchored to the keyboard for iOS

WeakSubscribe to events. Taken from the MvvmCross codebase and provided on its own. WeakSubscribe hands responsibility to the client code, unlike using a WeakEventManager which requires modified events. See project site for instructions.