Any card which offers a Priority Pass membership will allow you to enter participating airport lounges without regard to the airline that you are flying. You can buy a Priority Pass membership directly, but in the USA it is more common to buy a credit card which includes a bundled Priority Pass membership. Read about Priority Pass here: https://www.prioritypass.com/ Use the box in the upper left to lookup lounges at specific airports.

SJC and SFO both have two Priority Pass lounges.

At some airports, Priority Pass provides meal credits at Restaurants in addition to, or instead of, Lounge access. Note that the American Express version of Priority Pass excludes Restaurants, but does provide Lounge access.

Credit cards which offer Priority Pass include (there are others):

American Express Bonvoy (Marriott) Brilliant
American Express Hilton Aspire
American Express Platinum
Capital One Venture X*
Chase Sapphire Reserve**

*Capital One is also accepted at Plaza Premium lounges. Capital One has announced that they are opening a lounge network of their own. One location is open (DFW).

**Chase has announced that they are opening a lounge network of their own, but none have opened.