In addition to the American Express Blue Cash Preferred (not sure what limit it has on groceries actually, if any?), which I use for groceries...
Sallie Mae (Mastercard via Barclaycard): 5% on groceries, gas and bookstores (including Amazon) -- this has $250 limits on groceries, $250 gas so I only use it for gas/Amazon
Chase Ink (business Visa): 5% on utilities, internet, cell phone (and office supplies)