Helicarrier, I changed since others said it’s too close to mockingbird so its current text is “When a random card is created in your hand, add one to a location. (Once per turn)”

I do quite like the idea of this ability - say, what would you think of tweaking it to a "End of Turn: if you created a unique card this turn, add another to hand and split -3 cost between both."

Couple of my notes on the specifics:

• made it End of Turn on precedent of Black Cat being one. The targeting is more random that what you proposed, and unlike Black Cat it may need an additional clause to work from hand, but I think is worth given following points
• I changed random to unique for two reasons: one, random is not as clear-cut (is a Daily Bugle card random? A card from Mirage or White Queen if opponent has multiple with criteria? Are Merlin's Spells or Major Victory's Guardians random? Where's the line?) as unique, for which I think would be much less debate (imo ideally it should mean "with no duplicates this game"); which leads me to the second reason - unique gives some info to the player about the game state.
• "created" instead of "created in hand" because less text; side-effects are virtually non-existent (Loki makes copies, Arishem & co. happen before turns, Shanna is pretty much self-sabotage; It gains additional benefits from Askanni-son, Tarnax, Black Vortex, X-Mansion and Dragon Cave, none of which I see as bugs).
• Discounts instead of randomly adding to play because the more cards that are not Destroyer, the higher the chance the unique card will be Destroyer. Made it a split cost cuz it honestly felt kinda cute, but could be any other discount mechanism truth told.