Check for yourself: The three best tools are Cardmarket for a quick overview, eBay Sold Listings for rare special cases (e.g., serialized cards), and price lists/hotlists to see whats actually in demand
CURSED MIRROR This thing has had enough reprints now that basically any red deck can run it, and honestly
It looks like a chessboard being bent around like a handkerchief, while some chess pieces and actual people are being tossed around
Mai, Scornful Striker might be sideboard material at best, but I expect it to matter a ton against spell-based matchups
To get Tyrantrum to its throne on the battlefield, you need to get Antique Jaw Fossil into play first, so deck-searching Supporter cards like Team Rockets Petrel and Drayton are critical inclusions
TARDIS Showcase Treatments The TARDIS is travelling somewhere new: into the Magic card frame