The Sideboard The cards in our sideboard are designed to do three things: help improve our matchup against aggressive creature decks (by far our worst matchup), fight three-mana planeswalkers (especially Teferi, Time Raveler but also Narset, Parter of Veils and Oko, Thief of Crowns), and answer graveyard-based decks (which we actually help by filling their graveyard with our mill spells)
You could bring back the Pokemon Red & Blue memories with this little guy from May 1st through May 8th, 2020 with the Kanto Timed Research
Toxic Deluge is one of the best wraths ever printed but could be swapped with Storm's Wrath or Anger of the Gods for a less effective, but cheaper option
The Supply: Shockingly low print quantities, making them the holy grail for collectors
For example, assuming the Vaporeon card above is in lightly played condition, someone may offer TNTx2, which means they are willing to pay 26 x 2 = RM52
This is a big one that separates Arena from MTG Online and MTGA from IRL play which do offer trades