I find that the Uncommon slot of a pack really sets the tone for what kind of deck Im going to build in a Sealed event
Paradox Engine First Printed: 2017-JAN Banned: 2019-JUL Paradox Engine can be played in any deck, and creates large amounts of mana at little-to-no deckbuilding cost
Many of these creatures have powerful secondary abilities including creating additional creature tokens (Bladewing, Death Tyrant, Feldon, Kari Zev, Krenko, Mardu Strike leader), drain/life loss (Calculating Lich, Hellrider), direct damage (Combustible Gearhulk, Dreadhorde Butcher), anthem/buff effects for your army (Drana), card draw/free spells (Etali, Florian, Garna), additional combat step (Moraug), and many more
The recursion part
The combined creature will have (at least) two artists and may now have multiple colors