AmEx Blue Cash can earn you 5% cash back on gas if you use the card a lot. The catch, you only earn 5% after you have already spent $6,500 on the card year-to-date. The good thing is that you would earn cash back with Costco Gas.

Chase Visa also has 5% as mentioned previously, plus there are several other which offer cash back (Google: Gas Rebate Card) and AAA's Visa.