Better end the game quickly if you do that
We rebuilt that file many times, and playtested many times, so it was a lot of work
This means a Director Nick Fury deck can contain Blue, Red, White, Blue-Red (Izzet), Blue-White (Azorius), Red-White (Boros), and colorless cards
Are There Promo Cards
Even when you first-pick a card like Mister Negative or The Spot, Living Portal, you should probably be thinking of how to splash it into a UW or UB deck rather than trying to force pure WB its just too improbable
Permanents that allow you to tap your lands for any color, like Cromatic Lantern and The World Tree, make it easier, but if you don't have access to these permanents early, you may be stuck on having the wrong lands for what's in your hand.