If you have a sizable force, you cant go wrong with mass pump effects like Rally the Peasants or Heroic Reinforcements, provided you're in the right colors
Bloodletter of Aclazotz ($14.14) We've become so used to stronger, more recent cards having more lines of text that it's easy to overlook the value that Bloodletter of Aclazotz provides
At the start of each end step, you get to make 1/1 Rat tokens that are effectively Relentless Rats equal to the number of creatures your opponents control that were exiled that turn
Give that permanent or player another counter of that kind
But if you're a collector, you get a lot of premium stuff
Expect to see this stunning modern grail closer to the top of this list as time goes on, with the $2,000 plateau within sight