The Citibank DoubleCash card pays 2x cash back rewards on every purchase (redeem the reward as a direct deposit to your bank account, not to your credit card statement, for the full reward), has no caps or complicated quarters, & no annual fee. It does charge a foreign transaction fee.
The CapitalOne QuickSilver card pays 1.5x cash back rewards, has no annual fee or foreign transaction fee.
DS has these cards after building credit with a Wells Fargo reward card linked with his checking account. It only paid 1x & had to be co-signed (he was 17 when it was opened), but had no annual fee. He primarily uses the DoubleCash card, & uses the QuickSilver for overseas travel & backup. Why backup? Just yesterday, his DoubleCash wouldn't work because Citibank canceled it due to possible hacking of their system, but he hasn't received the replacement card yet. This happens all too frequently these days.