Abilities or mechanics complementing one another.
Cards have synergy with other cards if their abilities complement each other or proc other card abilities. Synergistic cards are thus often preferable over vanilla cards as they are able to generate more value. Cards that synergize with each other generally are the basis of any archetype.
It takes a lot of work to build, create, maintain and improve a free community site like this. We and third parties use tech like cookies to make this happen.