The model would either not respond or confuse cards, miss some or even hallucinate prices
From my own experience, when I was living in London Spanish, Italian and French cards were valued slightly lower than their English counterparts, both on player-to-player trading and on magiccardmarket.eu, and for both non-foils and foils including eternal staples like Thoughtseize
The defining mechanic in a multicolor block, persist is featured in all colors and on creatures of all sizes
The easiest way is with a Firebrand Archer, a cheap red creature printed in Foundations, which deals one damage to each opponent whenever you cast a noncreature spell
The biggest planeswalkers like Karn Liberated and Ugin, the Spirit Dragon
The value of X in the activation cost of Elite Arcanists other ability is the sum of the two cards converted mana costs