Five card types
Four of them stay on the table once played, and one never goes in a deck.
CreatureYour fighters. They stand in your row and attack with the power printed on them.
SpellAim it, cast it, and it's done.
TerrainA place behind your creatures that keeps working for you. Nothing can destroy it.
SummonA creature that another card brings onto the table.
ObjectBuilt, not born. It stands in your row like a creature, but most have no attack.
See also the seven categories and the thirty families.