If you combine the rarity of a limited release with solid mechanics and a beloved character, you've got the perfect formula for a valuable card
When you lose control of that Equipment this turn, if it's attached to a creature you control, unattach it
Not all of them are promo cards and not all of them come with the same criteria
Alpine Guide Arid Mesa Bedhead Beastie Bloodstained Mire Bountiful Landscape Cabaretti Courtyard Call the Mountain Chocobo Chartooth Cougar Cragsmasher Yeti Farseek Furnace Host Charger Gem of Becoming Grixis Panorama Hill Gigas Igneous Pouncer Jeskai Monument Jund Panorama Koth, Fire of Resistance Maestros Theater Mardu Monument Molten Man, Inferno Incarnate Mongoose Lizard Mountain Valley Naya Panorama Oliphaunt Perilous Landscape Riveteers Overlook Rocky Tar Pit Ruin Grinder Seething Landscape Seismic Monstrosaur Shard Convergence Shattered Landscape Sheltering Landscape Spoils of Victory Temur Monument The Cave of Two Lovers The Infernus There and Back Again Twisted Landscape Untamed Wilds Valley Rannet Wooded Foothills Zog, Triceraton Castaway
In other trading card news, Yu-Gi-Oh
A further variant introduced during Scarlet & Violet, Tera Pokmon ex, feature Terastallized Pokmon with a crystallised appearance in their artwork, potentially different types from the standard card and cannot take any damage while on the players bench