If an adventurer card ends up in exile for any other reason than by exiling itself while resolving, it won't give you permission to play it with its primary characteristics
A solid red commander and pretty popular in the 99, Purphoros, God of the Forge is a potent, and fairly pricey card: The regular version for the original Theros printing sits around $25, and later premium versions are close to $50
Ursula is worth every bit of ink she costs, offering massive defence, lore and card draw on a single card - an essential inclusion in any amethyst deck
Vivi Ornitier generates mana equal to his power every turn, Blue or Red, and only costs Three mana
Some older cards have received errata to instruct a player to mill cards rather than to put the top cards of their library into their graveyard