Some are frustrating, some have the potential to be overpowered, and some are just heartwarming, but still silly
This human knight is feared for its ability to end games in a heartbeat if you're not prepared to block
As it happens, End Hostilities is efficiently costed at only five mana, and even has another important ability to boot: "and all permanents attached to creatures." This means Equipment, Auras with bestow, and other Auras attached to creatures (these would normally die along with the creatures, but it could come up that they're still destroyed if the creature is indestructible or gets regenerated)
Warning: Do not sell an entire collection to a shop without removing the rares and expensive uncommons first
When you scratch your head and think "How the heck am I going to win with Squirrels?!?", think Overrun, Centaur Chieftain, or even Lure
Mana, cards, and early pressure in one creature pushed him to the top of Modern