Being one who doesnt want others to change their decks by some autocratic decree or campaigning for house bans, I set upon a quest to build a control-killer
Finally, there was a rare creature cycle where every card's mana cost was four hybrid enemy-color mana
Enchantment The Aetherspark As long as The Aetherspark is attached to a creature, The Aetherspark can't be attacked and has "Whenever equipped creature deals combat damage during your turn, put that many loyalty counters on The Aetherspark." +1: Attach The Aetherspark to up to one target creature you control
Out of the three of them, I think Jace, Wielder of Mysteries is the perfect mix of usefulness and power: he can be played early in the game for advantage, but he also encourages combat as he can be attacked directly
Just a quick note, all these prices come from TCGplayers Market Value and are subject to change