Card sounds may differ from in-game as they get updated.
Flying - Flying units can only be blocked by other flying units, but can block ground units normally. They can also be directly attacked by Killer units and Relic Weapons.
Reckless - Units with Reckless must attack.
Summon - Does something when played
Nightfall - The first Nightfall card played in a turn makes it Night and extends it by a turn for each player.
Night - When you start a turn at Night, draw an additional card and take 1 damage.