Across all categories, card value usually comes from: Scarcity (low print runs or no reprints) Demand (Commander, Legacy, collectors) Condition (graded cards sell higher) Aesthetic appeal (art, foils, alternate versions) Historical importance (early sets, iconic cards) How to Sell Magic: The Gathering Cards Safely If your cards have value, you can sell them through trusted channels
When creating unique decks or sets with customized mtg rare find abilities, its important not overlook these determining factors such as casting-cost
As opposed to cards like Moat that just leave your opponents creature in play (until the can find an answer), The Abyss will destroy these creatures, and even prevent your opponent from continuing to play creatures (on account that they will eventually be sacrificed)
While with Scars of Mirrodin the emerging Phyrexian threat was just that, a dark undercurrent threatening to topple a well-buffed metallic utopia, with Mirrodin Besieged there can be no doubt that the Phyrexians have arrived, and they mean business