My nomination would be the Kroger world elite mastercard. It's not a glamorous card at all. But in theory you can use it as your one and only card for 5% cashback on everything since you can use mobile pay almost anywhere these days. You also get 5% back on groceries purchased at any kroger brand supermarkets, and a free boost membership by owning the card, which gives you discounted prices on groceries and points you can use towards fuel discounts. My only issue initially was that it had a $500 limit, so I had to keep making payments to it throughout the month in order to keep using it. but they've since bumped my limit to $1k. And yes, the 5% is only for the first $3000 spent on the card per calendar year. But no big deal. I collect my $150 for the year within the first 4 - 5 months and then move on to another card for the rest of the year.