however, they are not necessarily rare because they are so expensive - many of the rarest cards were given away for free, or could be pulled from packs
White Rares Wrath of God $300/$200 Animate Wall $160/$80 Armageddon $150/$100 Balance $150/$100 Crusade $100/$60 Island Sanctuary $100/$60 Northern Paladin $100/$60 Purelace $100/$60 Savannah Lions $100/$60 ALL OTHER WHITE RARES $80/~$40 Blaze of Glory $60/$30 Blessing $50/$25 Of these, Animate Wall, Island Sanctuary, Northern Paladin, and Purelace are likely outliers due to single-owner hoarding
You can cast Control Magic to take control of an opposing Purphoros, God of the Forge if its a creature
it's an ok ability I guess
Practical scarcity today is driven less by the original pull rate and more by how few copies grade well
We're leaving these somewhat mysterious for those who want to have that experience, but if you want to know what they all do, you can hop on over to the Release Notes