Pre-global release Japanese exclusives
You can't choose multiple creature types, such as "Human Survivor." Card types such as artifact can't be chosen, nor can subtypes that aren't creature types, such as Kaito, Vehicle, or Treasure
Within a God Pack, the distribution is as follows: 1: 40% 2: 50% 3: 5% : 5% This means each card in a God Pack has a 5% chance of being a Crown Rare, significantly higher than in standard packs
The Slowlands: These were expensive during their heyday in Standard, and the premium versions still are
III Tap all creatures your opponents control
The Ur-Dragon is the quintessential dragon commander, making your dragons cost 1 less even from the command zone while allowing you to play any color of dragons in your EDH deck