Mirrodin Besieged has variants:
Explore this pack in Sealed.

Sheets

Sheet basic

At rate 1/10 (10.0%)

Sheet common (color balanced)

At rate 1/60 (1.67%)

Sheet uncommon

At rate 1/40 (2.5%)

Sheet rare_mythic

At rate 1/40 (2.5%)
At rate 1/80 (1.25%)

Sheet foil

At rate 3/350 (0.86%)
At rate 1/160 (0.63%)
At rate 3/800 (0.38%)
At rate 3/1600 (0.19%)