In terms of the less rare items mentioned, they can be awesome game pieces too if you have that level of disposable income
Sokenzan, Crucible of Defiance may not be as good as Otawara, Soaring City or Boseiju, Who Endures, but it fits into what red decks want to be doing, and Ive set up my share of lethal attacks thanks to the Kamigawa land
Catharsis Catharsis hits hard
Marcy: Nice banner effect, good ramp for your expensive Eldrazi (or other colorless) bombs
For example, if Warrior is the chosen creature type and you control Bramblewood Paragon (a creature with "Each other Warrior creature you control enters with an additional +1/+1 counter on it."), a Runeclaw Bear would enter with an additional +1/+1 counter
There were dozens of cards released with unique serial codes, and, while they are expensive and easily the biggest chase cards from that set, the idea felt almost too ridiculous for anyone but the most avid collector