Salt or salty has to do with negative feelings about a particular card
However, MTGGoldfish is listing the individual values of these cards as anywhere between $6,000 and $49,500, which is remarkable, and it feels unnaturally inflated right now

3,273decks Jenson Carthalion, Druid Exile 3,029decks Tazri, Beacon of Unity 2,896decks Kyodai, Soul of Kamigawa 2,548decks Cecily, Haunted Mage // Othelm, Sigardian Outcast 2,420decks Sliver Gravemother 2,346decks Niv-Mizzet, Supreme 2,251decks Tazri, Stalwart Survivor 2,212decks Sliver Queen 2,150decks Mass of Mysteries 2,076decks Atogatog 2,070decks O-Kagachi, Vengeful Kami 1,985decks Thanos, the Mad Titan 1,909decks Cromat 1,721decks Jegantha, the Wellspring 1,700decks Leonardo, the Balance // Raphael, the Muscle 1,562decks The Fourteenth Doctor // Clara Oswald 1,521decks April O'Neil, Live on the Scene // Leonardo, the Balance 1,231decks Sliver Legion 1,228decks Super-Skrull 1,131decks Donatello, the Brains // Leonardo, the Balance 959decks Leonardo, the Balance 831decks Karolina Dean, Runaway 643decks Vorthos, Steward of Myth 307decks Leonardo, the Balance // Splinter, the Mentor 290decks The Fourteenth Doctor // Vislor Turlough 205decks

Goblin Wizard Goblin Wizard beats out Warren Instigator and Goblin Lackey by simple virtue of not having to attack and risk its life for that extra free goblin
Greedily, he tried to gobble up everything he could
They look rough, often just photocopied text, handwritten notes, or stickers on a card, because the goal was simply to see if the ideas worked during gameplay