(Treachery is best played with Commander/EDH: see mtgcommander.net for more informations about this format.) However, due to the increased political nature of Treachery, and the fact that all the players start the game being opponents to each other, some cards should not be played without prior agreement from the other players in the game, and may steer your playgroup to avoid other, similar cards
We agree in some places, and disagree in others
Their mechanic could be as simple as keywording the if you have gained life this turn triggers from their Strixhaven cards, the way morbid does for creatures dying
Final Fantasy IX [] Silence is a White Magic spell usable by Dagger, Eiko, and Beatrix
The effect would already be pretty crazy if it let you play a card for free from your hand, let alone search it out from anywhere, basically letting you pull out your I win card at will