Costco Amex, cashback annually:

3-4% on gas
3% on restaurants
2% hotels, rental cars, airfares

Amex Blue Cash. 5% cashback on gas, groceries, pharmacy after you hit $6500 spend for the year. You can buy hotel/airline/restaurant giftcards at the grocery store and get the 5%. Even ebay/Paypal cards I have been told.

Free Hilton Amex gives 6 HH points per dollar on Hilton spend and some other categories. Worth around 3+%. $75 a year Hilton Surpass Amex gives 9 HH points per dollar and Diamond if you hit $40K for the calendar year.

There is some 3% cashback card for all airfare out there. Not sure which.

If you have someone to travel with, the WN Companion Pass is well worth shooting for. I am looking at 5+% value on specific CC spend.