pokemon cards with cynthia 148/156 and her Garchomp has been by her side since the very beginning! Pokemon Card - S&M: Ultra

[1] The "Compilation of Uncut Sheets" thread on the Magic Librarities Forum has pictures of all three sheets.

This means they arent so much unique promo cards, as much as they are just a guarantee that players will get these specific cards

Suddenly counter target spell, destroy target artifact, cast an artifact spell, and put an artifact onto the battlefield all stop feeling like random phrasing and start feeling precise

They are used or given at different MTG events

Once you have your timewalks the rest of the deck is usually just a bit of green ramp (primarily of lands so as to thin then deck), perhaps a stalling Wall of Blossoms, a bunch of card draw and then recursion and reshuffle effects