As far as credit cards. The three cards that I carry are AmericanExpress/Costco card, the Citibank Dividend card, and the Citibank Shell Mastercard.
I use the Costco amex card as much as I can, use the shell mastercard only for gas (when I can’t get gas at costco), and the dividend card for everything else.
If you do a lot of international travel, the only card company that I doesn’t charge exchange fees is from Chase (so some have posted).
All the cards mentioned above don’t have fees (the shell card fee is waved if you purchase 1 tank a gas per year from shell).