To see where this is coming from, we need to look back where this started
Timmy's a reference to a system of how M:TG classifies its players, and there's a Timmy inside every one of us
Still one of the top decks of the game, with OP5 he gains good cards, especially Amaru
That sort of bright colors, crisp, pop look that the art has is something he sort of tweaks out from every artist so that gives the game sort of a unified look to the art
At the beginning of the next combat, return those cards to the battlefield under their owner's control and those creatures gain haste until end of turn
League Challenges are entry-level, and League Cups are just a step above, making these the least competitive of the lot