The Amex Express Blue Cash Card has solid benefits for those who spend a lot on gas and groceries:
After spending $6,500, you earn 5% on gas and groceries and 1.25% on everything else. Before you reach $6,500, it earns only 1% on gas and groceries and 0.50% on everything else. There's no annual fee.
However, there are a few downsides which are described in this Nerd Wallet blog post