Its specific best-use case is with Super Hippo Carnival, but it can be used in other situations
Droll also affects you as well, since it applies to both players
I still have to say, Gen 3 wins for most legit legendaries in design, story lore, and impact

Steal Enchantment An aura to place on an enchantment You gain control of enchanted enchantment Aura Thief When it dies, you gain control of all enchantments (auras stay attached to whatever they are already attached to, but you control them) Kefnets Last Word Gain control of creature, artifact or enchantment, but your lands dont untap for a full turn afterwards Aura Graft Allows you to gain control of an aura and choose a new target to attach the aura to Archmages Charm Can gain control of any nonland permanent with mana value 1 or less Blatant Thievery Gain control of any permanent from each opponent, including lands Agent of Treachery Gain control of any permanent upon entering the battlefield, including a land Kiora Bests the Sea God A saga whos Chapter 3 lets you gain control of any permanent, including a land Countering Enchantments There are heaps of cheap costed (2 mana value or less) counter spells you can cast that can counter any noncreature spell, or even any spell period

Granted these raw cards wont be pack fresh but I think a big thing I learned is that pack fresh cards rarely get a PSA 10 anyway