Bonny Pall is a big hitter that draws cards, plays or reanimates land for free, and drops a huge blue ox that gets stronger and stronger right onto the battlefield into the bargain
Others have to use tricks like casting Deep Analysis to force you to draw cards and would otherwise have no game at all
Hildibrand Manderville would have been a really interesting card to see in the main set, at least mechanically
Regardless of what cards were added in the flex slots, the deck won by playing out a massive number of creatures, attacking with them, and then sacrificing them to drain out their opponents with [card]Blood Artist[/card] triggers, amass an army of flying demons courtesy of [card]Skirsdag High Priest[/card], or just create a giant [card]Voice of Resurgence[/card] token to bash their opponent to death with
Did I miss any that you think should be here, or on the flip side, did I list an undeserving shifter