Raid

Raid is an ability word introduced in Khans of Tarkir, wherein it is the Mardu Horde clan mechanic. It gives an advantageous effect if a player has attacked with a creature the same turn. Mark Rosewater considers Raid to be a mechanic that will be revisited more than most because it's well liked, plays well and has a lot of design space, but it's not the kind of thing to become evergreen. Raid reappears in the Ixalan block, where it is the signature mechanic for the pirates of the Brazen Coalition.

Rulings

 * Raid abilities care only that you attacked with a creature. It doesn't matter how many creatures you attacked with, or which opponent or planeswalker controlled by an opponent those creatures attacked.
 * Raid abilities evaluate the entire turn to see if you attacked with a creature. That creature doesn't have to still be on the battlefield. Similarly, the player or planeswalker it attacked doesn't have to still be in the game or on the battlefield, respectively.