Ever since the early days, specific creatures, spells, and artifacts have been far too powerful for the meta, forcing Wizards of the Coast to start restricting cards
That means you can either play them like normal as a land drop, or you can alternatively cast the adventure part of the card
The more mana you spend on it, the more dice you need to have at your disposal

Commander 1Vaevictis Asmadi Creature 1Birds of Paradise 1Wall of Blossoms 1Wood Elves 1Yavimaya Elder 1Yavimaya Granger 1Argothian Elder 1Willow Satyr 1Silverglade Elemental 1Crater Hellion 1Multani, Maro-Sorcerer 1Thunder Dragon 1Verdant Force 1Zodiac Dragon Sorcery 1Imperial Seal 1Reanimate 1Demonic Tutor 1Nature's Lore 1Rampant Growth 1Three Visits 1Buried Alive 1Grim Tutor 1Wheel of Fortune 1Yawgmoth's Will 1Ambition's Cost 1Ancient Craving 1Creeping Mold 1Relentless Assault 1Living Death Instant 1Berserk 1Crop Rotation 1Vampiric Tutor 1Constant Mists 1Price of Progress 1Reap 1Corpse Dance 1Harrow 1Necrologia Artifact 1Fellwar Stone 1Horn of Greed Enchantment 1Burgeoning 1Carpet of Flowers 1Elephant Grass 1Exploration 1Wild Growth 1Animate Dead 1Compost 1Fertile Ground 1Fervor 1Grim Feast 1Necromancy 1Necropotence 1Overgrowth 1Defense of the Heart 1Grave Pact 1Greater Good 1No Mercy 1Pandemonium 1Sneak Attack 1Black Market Land 1Ancient Tomb 1Badlands 1Bad River 1Bayou 1City of Brass 1Diamond Valley 12Forest 1Grasslands 1Karplusan Forest 1Maze of Ith 4Mountain 1Mountain Valley 1Phyrexian Tower 1Reflecting Pool 1Rocky Tar Pit 1Sulfurous Springs 8Swamp 1Taiga 1Yavimaya Hollow I was honestly shocked at how fun and cohesive this deck ended up being

Often considered to be the rarest Pokmon card of all, the so-called Pikachu Illustrator (its proper name is Pokmon Illustrator but no one calls it that) was a print of around 41 cards given to winners of a Japanese competition in 1998