Celes, Rune KnightCeles, Rune Knight has both an incredibly powerful enters ability, letting you filter and add to your hand, and a passive ability that lets you trivially win the game with a persist creature, such as Murderous RedcapMurderous Redcap, and a sac outlet, such as Viscera SeerViscera Seer or Goblin BombardmentGoblin Bombardment
It was an experiment in creating a 'pack-cracking experience' rather than a draft-optimised product, and it split the player base between those who loved the bonus slots and those who found the randomness frustrating
They often work within communities, either from above as a leader or from within as a healer, bodyguard, or just a loyal follower
(The common and uncommon showcase cards appear in the previous slot.) Note that neither of these is your rare slot, so any rares or mythic rares you get in these two slots are extra ones in the booster