Deutschlandcard is pretty useless unless you are a big fan of Edeka chain (Marktkauf, some of the Edekas - the one on Kieler strasse in Hamburg doesn't accept it), or you tank regularly at Esso.

Oh there is also a Shell card for Germany too.

If you tank a lot at Aral - payback card can generate you quite some points (you get a coupon for more points). I hardly tank there since it's more expensive.

It helps a lot that now Rewe is part of Payback too.