Rarer than even enchanted, iconic cards use new art and a brand-new foil treatment that coats the card in glittering lore symbols and 3D hot stamp effects
This was in part due to Wizards' inability to accurately predict what would be the card to see play and what wouldn't
Crypt Ghast and Nirkana Revenant are good choices as well because they can double your mana pool, and with Urborg, Tomb of Yawgmoth all your lands can work with this effect
Along with the anthropomorphic animals featured above, which see a Mouse Soldier, Otter Rogue and Rabbit Soldier springing into action, a more traditionally quadrupedal bear also features
Goblin Blast-Runner doesn't need to have been on the battlefield at the time the permanent was sacrificed in order to get the bonus
I've only ever heard of this approach being done with power, but as we'll discuss later, the astronomic rise in card prices provides more incentive to fake cards