Recurring Nightmare If you want to do fundamental unfair things in a non-EDH format, look no further than Recurring Nightmare and its busted play pattern
Damaged, miscut, heavily played, or glare-heavy cards may require manual lookup
While leveraging quirks like targeting a creature with "can't block" would be fun and is fine to reward, being able to target tapped creatures is clearly too easy and against the spirit of the card.
At the beginning of combat on your turn, you may have Gogo, Mysterious MimeGogo, Mysterious Mime become a copy of another creature you control until the end of the turn - but since Gogo keeps its name, you're free to copy legendary creatures too
Yuya was initially afraid to summon the four dimension dragons out of fear it will awaken Zarc's soul within Riley, until his counterparts helped him realize that they inherited Zarc's ability to communicate with Duel Monster Spirits
For blue decks, their best play against enchantments is to simply counter the most threatening auras