A card can be valuable because it is powerful in one of these formats, especially Commander, which has a huge casual player base and constant demand for unique cards
Just one plane is a blank on this, Mount Keralias ability to prevent damage to your stuff from Mount Keralia
Acrobatic Maneuver Astral Drift Astral Slide Bind (playtest) Blizzard Strix Blur Brokers' Safeguard Cloudshift Conjurer's Closet Daydream Essence Flux Icy Prison Justiciar's Portal Liberate Long Road Home Mistmeadow Witch Otherworldly Journey Parting Gust Pegasus Guardian Pegasus Guardian Personify Quantum Entanglement Restoration Angel Sentinel of the Pearl Trident Siren's Ruse Skybind Skycoach Conductor Spaceshift Tawnos's Coffin Teferi's Time Twist Turn to Mist Vanish into Memory Vizier of Deferment Voyager Staff
The more tools that are out there to help folks find good, fun games of Commander, the better
The lawsuit was specifically triggered by Dark Kadabra from the Team Rocket set, which portrayed the Pokmon as an evil character, something Geller objected to strongly
Specifically, Arthur pairs really well with Madam Mim Purple Dragon and various Merlin cards