Is there an expansion for Archwynd?

Yes! The expansion for Archwynd is called Archwynd Vale.

Archwynd Vale requires the base game of Archwynd in order to play.

Archwynd Vale adds support for up to six players, plus additional Heroes, Monsters, Traps and Benisons. More importantly, however, Archwynd Vale also provides an advanced set of rules that enables you to customize your Hero into thousands of configurations so you can play your Hero the way you want.