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Dicover It Miles is a 3% cashback on everything card for the first year, after that its just 1.5%.
BoA has been mentioned. But the TR card hasn't been named yet. At Platinum Honors Preferred Rewards it earns 2.625% cash back. But it can only be redeemed against travel expenses. Although, there is a loop hole if you have a world points BoA card (e.g. Fidelity Amex).
There are also many travel cards that can earn 2.5% cash back depending on how you redeem it. As in, redeeming the miles for first class international flights.
I guess we could also include the BoA BBR card, but only for people who don't spend much.