Flash lets you play a card at instant speed, meaning on your opponent's turn and in reaction to other cards being played
You basically just need a card or two to turn this into something obnoxious
The cards arent covered by the comprehensive rules and are not for tournament play, notably different from being not tournament-legal. While it's true that silver-bordered cards arent legal in any Standard, Vintage, or Modern decks, Wizards still intended them to be used in casual black-bordered formats rather than exclusively with each other
A colorless symbol (a white star) can be fulfilled by any type of Energy
You want a little more durability without spending too much, so is there a sweet spot in the middle
Once you pick a specific time-slot, if sign-up rules werent listed on the event page in the Companion app, give the store and call and ask how you can sign up