To give a Guideline on how to create a card that is balanced and could be implemented into the game you can use the following stats. All cards, depending on their card level, have a minimum and maximum of allowed stats. Furthermore a card can have a maximum of 3 Range and 3 Movement. (Of course its allowed to create unbalanced cards as well) :D
These numbers represent all stats on a card combined. Alnarasz for example sums up a total of 23 stats, which is the minimum for a Hero card.
If you have any questions let me know in the comments here or below the video, and have fun making your own cards!