I don't usually like 3-cost mana rocks, however, it can untap a legendary creature and Shadowheart needs to tap to use its ability, so I will make an exception
This white instant works best in decks with lots of powerful enters abilities to retrigger, which gives it utility when you dont have to protect your creatures
Again with flavor, efficiency, and fun
When you "flicker" a permanent, it's treated as a new card that just entered the battlefield
If thats not your thing, here are some other options: Zareth San, the Trickster Varragoth, Bloodsky Sire Thieves' Guild Enforcer Whispering Madness Reconnaissance Mission Coastal Piracy Bident of Thassa Mask of Memory Cloak and Dagger Blighted Agent BATTLE YOUR FRIENDS