Eldrazi kindred decks featuring Zhulodok, Void Gorger or Kozilek, the Great Distortion need colorless mana sources to cast creatures and spells
Yugi drew Silent Swordsman LV3 and then Tributed his Yellow Gadget to Summon Summoned Skull
There are a total of seven Attributes available and serves as the Digimon's type
Sephara, the Sky Blade is a good representation of a type of deck players will see in Constructed formats, but this deck also includes some good value
Hating on Collected Company, Goryo's Vengeance, and Through the Breach is a big deal all by itself, and when you throw in all of the other weird cards that Mistcaller happens to be good against, it wouldn't be surprising to see people try to squeeze a copy or two into their sideboards
Many of the best also have a rather low casting cost, allowing them to hit the battlefield early and start generating value