I can only find the USD$ and GBP£ cards. I'm in Saudi Arabia, Blizzard set the currency of my battle.net account to EUR€, so I can't buy things from their stores with GBP or USD cards unfortunately.
This is to inform you that the EUR20 Battle.net Gift is now available in our website. You may proceed to place your order now.
EUR20 Battle.net Gift Card (EU)
Should you have any inquiries or require any assistance for your order, do not hesitate to send us your inquiries. We're always ready to assist you the best we can.