Core Set 2021 has variants:
Explore this pack in Sealed.

Sheets

Sheet basic_or_gainland

At rate 1/20 (5.0%)
At rate 1/40 (2.5%)

Sheet nongainland_common (color balanced)

At rate 1/101 (0.99%)

Sheet uncommon

At rate 1/80 (1.25%)

Sheet rare_mythic

At rate 2/121 (1.65%)
At rate 1/121 (0.83%)

Sheet foil

At rate 3/655 (0.46%)
At rate 1/320 (0.31%)
At rate 3/1210 (0.25%)
At rate 3/2420 (0.12%)