One of the reasons decks with more than three colors are less popular is that it's just harder to make the mana work
Simon, Wild Magic Sorcerer / Mathise, Surge Channeler You want to build around the group hug nature of forcing your opponent's to draw cards before you jump in with Simon, Wild Magic Sorcerer / Mathise, Surge Channeler
In MTG, it becomes an effect that causes something to happen if you attack with a group of creatures with a power of six or more
And for an instant win setup, pairing it with Wound Reflection means a player with 20+ life drops down to 10 and then immediately falls to 0 at end of turn a simple two-card combo that ends games fast and dramatically
Brass's Bounty gives you tons of Treasures on the spot to feed into your win conditions
Vivien does cost six, but at least it does something when you cant get a Pod chain going