Flash is a mechanic that allows you to play a card any time you would be able to cast an instant (essentially, whenever you want in most circumstances). As stated on MTG Salvation, King Cheetah was the first card released with flash.

Originally from Visions, King Cheetah really isn’t a very impressive card, but being a 3/2 with Flash for 3G isn’t terrible during that time, though it’s not a card I recommend now. The actual mechanic wasn’t called flash until Time Spiral, which included significant cards such as Teferi, Mage of Zhalfir.

Flash is an evergreen concept, being used in almost every set, though the best known card of this would be the famous Snapcaster Mage.

Notable cards with Flash:

  • Teferi, Mage of Zhalfir
  • Snapcaster Mage
  • Ambush Viper
  • Yeva, Nature’s Herald
  • Jin-Gitaxis, Core Augur
  • Aven Mindcensor