Carding involves hacking of cards where carders use different techniques to enumerate card numbers to get working combinations.
Gift cards

Gift cards are used more often because they can be easily resold on the dark web. Gift cards have a low level of protection: they don't have names, zip codes or addresses associated with them. Moreover, many online stores create a separate page for gift cards, which can be easily used by carders.
Carding services

There are carding services, such as Cvvshophighbalance, 101dumpswithpin and Creditcarddumpsites that have stepped up their game by using bots that can mirror human behavior.