American Express, also known as Amex, is a multinational financial services corporation based in the United States. Founded in 1850, American Express is known for its credit card, charge card, and traveler's cheque businesses. 

American Express offers a range of credit cards that cater to different lifestyles and needs. Some of the popular American Express cards include:

1. **The Platinum Card® from American Express:** This premium card offers luxury travel perks such as airport American Express lounge access, hotel elite status, and annual travel credits.

2. **American Express® Gold Card:** This card offers rewards on dining, groceries, and travel, as well as travel credits and dining benefits.

3. **American Express® Green Card:** This card offers rewards on travel and dining, as well as travel credits and other travel-related benefits.

4. **Blue Cash Preferred® Card from American Express:** This card offers cash back rewards on groceries, gas, and transit, as well as other everyday purchases.

5. **Delta SkyMiles® Credit Cards:** American Express offers several co-branded Delta credit cards, each with its own set of benefits and rewards for Delta Air Lines loyalists.

American Express cards are known for their customer service, travel benefits, and rewards programs. However, they typically have annual fees and may not be as widely accepted as Visa or Mastercard, especially outside the United States.