As a long term Hearthstone player, I myself have been very eager to make my own cards since I joined the HS community, but, for some weird reason, there was only the possibility to make custom .pngs of cards. So, here is my soft to make animated card plays, alike Fulla's channel W/O any work with AfterEffects etc.
To summarize, after downloading and extracting, you only need Cards folder and HSA_start.EXE. You edit .pngs with something like PAINT.NET inside \CardConf\Cards, and then everything through else through HSA_start, and then in Cards. (make sure not to change image width and height, as well as format .png)
Apart from .png editing, everything should be straight forward from within HSA_start. Anyway, detailed tutorial here.
Right-click to save video (do not rename video in save dialog, otherwise it will not save <- known bug)