As in draft boosters, set boosters will feature a guaranteed rare/mythic rare card, but with a higher chance of mythics appearing in both draft and set boosters from Zendikar Rising onward
Of course I include cards that destroy everything, but mass exile and mass bounce are on the table as well
I cant imagine the three-mana cleave being efficient enough to see play there
And Starfall Invocation is an unconditional battlefield sweeper for creatures, with an optional gift cost that can bring one of your creatures that died back to the battlefield
Shantotto, Tactician Magician A limited focused card for the UR cast big spells archetype which seems like a perfectly decent little dude, who also loves affinity for artifacts
Purphorus, God of the Forge 9/10 Very powerful and often pretty inevitable