Scaleform is available through Autodesk as a seperate license and integration. There is also a number of webkit UI’s available on the forum. 's VaQuoleUI being one, CoherentUI is also available for a cost. Then there is slate which comes with UE4 (Epics own UI solution) which requires building the UI’s in C++, and UMG is in development as we speak (WYSIWYG Slate editor with other fancy features)