Weve all been on the receiving side of a turn-1 Sol Ring + Arcane Signet start, allowing someone to cast a 4- or 5-drop commander on turn 2
Whenever he or another of your creatures dies, you can grab a creature with lower toughness from your graveyard and add it to your hand
However, unless you are truly a honed veteran, I would try and refrain from playing more than three colorsas tempting as it may be
Whereas way back when you could draw a card, play a land, play a creature, and get to make another attack (still very good) the general power level of MTG cards has increased to the point that players can achieve so much more in a single turn
For a Mana Value of just GU (one green mana and one blue), Doc Aurlock offers incredible cost reduction that plays into Thunder Junctions new Plot mechanic, while being broadly useful across multiple existing formats other than just Draft