Mistveil Plains A tapland, yes, but Mistveil Plains is a combo/synergy piece with all sorts of commanders, including Quintorius, Field Historian and Djeru, With Eyes Open among others
Motivated Pony Motivated Pony is right at home with its fellow Lord of the Rings Food cards
Eerie Uh, yeah
If a player offers a final guess that is incorrect, they are not removed from the game like in the Clue board game, they just no longer can solve the case leaving them the option to win the game via defeating the other players in the game of Magic
Getting to remove two opposing problems, or remove one and pull two cards ahead, is a massive tempo swing
On a negative note, Skarmory is indeed a Mega Evolution, which comes with the clear risk of giving a lot of advantage to your opponent if it falls in battle, so that is the entire reason why I didnt dare include it higher on the list