Imprint was a mechanic from Mirrodin block (and later reprinted in Scars of Mirrodin block) where the player had to exile a card when casting the spell (the exiled card came from different places), which then was used as a marker to determine something about the spell
That said, Im intrigued by the idea of Elder Language Highlander decks and curious how the format might play out
The power of card-draw and Energy acceleration to fuel these expensive attacks is what determines their viability, not the attack effects power on its own
Sphinx of Clear Skies The Fact or Fiction reference frequently comes up on sphinxes to evoke the idea of giving your opponent a riddle or dilemma to sort through
You'll find Mega Charizard X ex here as a foil promo card, along with another foil promo card featuring Oricorio ex to help get more Fire Energy into play
Their print runs are not infinite, so even these products can appreciate over time just usually slower than JP/ENG