If you really want to get serious about a card set for travel, do some research and figure out what you want a card for, which may wind up being more than one card.
I have one card for daily use, has a bunch of travel perks (free bags, lounge access, premium rental auto insurance, some other coverages) plus helps me maintain status (so far) It also accrues miles/points that can help get free tickets or upgrades. It is one of the Delta cards, but every airline has something, and general cards like the Chase Sapphire or Capital One Venture series also work. Which one is best really depends on how you travel, how often, and how much you spend in a year.
If you are looking at a card for points/miles for tickets, be prepared to charge tens of thousands of Dollars a year to see a real benefit, also verify that those points do not expire, or you can try the card churn thing and nab intro offers each year.
However, for a card to use while traveling, I went a whole other way. I have a UNFCU Elite Visa, it is highly secure, is PIN Priority (I enter a PIN for any large purchases that are not contactless), and has 3DS for online purchases. It has worked in about any conceivable transaction in Europe, I have avoided issues seen on here with unmanned kiosks, websites that will not process a charge, and a variety of other issues.
I do also have my Schwab Debit card, not for charges, but for cash withdrawal. As others said, the main attraction is refunded ATM use fees.
Of course, when I travel I have those cards with me (scattered in different locations) and usually have 3 credit cards and 2 debit cards, not counting what my wife might have.