Here's a breakdown of what you'll find in a Commander Legends Collector Booster:

2 extended-art cards (1 C/U and 1 R/M)

1 foil-etched showcase legendary mythic

1 foil-etched showcase legendary R/M or foil borderless planeswalker

1 foil-etched showcase legendary uncommon or foil-etched showcase Prismatic Piper

1 foil rare or mythic rare (30% chance of extended-art foil)

2 foil legendary U/R/M

2 foil uncommons (each with a 20% chance of being upgraded to a foil extended-art common or uncommon)

5 foil commons

1 foil token
Contents:
1 Sealed Collector Booster Box
‣ 12 Collector Booster Packs