We basically buy almost everything with CCs that have cash back and they are paid in full every month.
Our gasoline, diesel and propane cash back card is the PenFed Cash Rewards which pays 5% cash back every month. It's used at the pump and good in the US and Canada. They do require a second account and I have a $25 money market account that paid a few pennies over the years. For truck stop fuel pumps for truckers where I pay inside I use an AmEx card that pays yearly cash back.
And we also buy some of our groceries at Krogers (often a Frys brand) and right now have $0.70/gallon off of their fuel for 35 gallons.