all praetor cards mtg Hand of the Praetors - Single Card Haste At the beginning of your upkeep Praetor's Grasp | New Phyrexia

In terms of other pricey cards that arent as notable, youre looking at Calculating Lich, Seasoned Dungeoneer, and Grim Hireling which all float around the $10 range

There must be four or more card types among cards in your graveyard in order for these abilities to trigger

The +1 sacrifice effect can break through in games where the board has stalled, or even set up some graveyard shenanigans as a sacrifice outlet

Whether or not well see this mechanic later on other planes is currently unclear, but there doesnt seem to be any problem with it balance wise

Human decks that go beyond Boros or Selesyna are usually in blue (if not all colors), and dont tend to struggle for card draw