The other use I can think of is that Karn's card draw isn't worded as "drawing," so if you're a horrible person and want to lose your friends, you can pair Karn with mean cards like Possessed Portal or Omen Machine to lock them out of the game while you keep your hand nice and full
Polukranos, World Eater Polukranos, World Eater saw play mainly as a 5/5 for 4 with an upside, and anything with two colored mana symbols is fair game in the green devotion decks
In Magic , that same logic applies, as this green powerhouse already comes in at an incredibly good rate: for a 7/7 with both reach and trample a strong creature in its own right
(Though, if you have enough mana fixing, you could maybe splash for a third color if you wanted.) But if you want to shop around to other colors (what's more Dimir than having a Dimir deck box when you're actually playing Selesnya, I suppose?), things that may draw you into specific colors are: A really strong rare you're excited about
Bristly Bill does a great job circumventing one of the issues with counter doublers that need another source to add counters in the first place
Do Unstable basic lands and Amonkhet Invocations (both cards where the art goes to the edge of the card) have borders for the purpose of this card
