You can build a Draft or Sealed deck any way you want, including a deck that plays more than two colors
5 Ezio Auditore da Firenze Requiescat In Pace You might look at Ezio Auditore de Firenze and see the five color ability that forces a player to lose the game as the main win-con, but it's a distraction from the truly powerful ability
More importantly, there are a ton of tools for mitigating the usual aura drawback of getting yourself two-for-oned
Cards with death triggers, like Jenova, Ancient Calamity, can also be helpful since they give you value when your cards are destroyed, which compliments wanting a full graveyard
The deck wants to build a massive engine with Kilo, Apogee Mindand win via alternate conditions like Darksteel Reactor
Tolls is an Orzhov two-drop enchantment that also arrives with a Clue and then turns sacs on my turn into a 1/1 Ally