Skins from The Ancient Collection are only available for purchase for Operation Broken Fang Premium Pass holders.
The Ancient Collection is a Valve-made collection of CS:GO skins introduced on 03 December 2020. The collection consists of 5 consumer skins, 4 industrial skins, 4 mil-spec skins, 3 restricted skins, 2 classified skins, and 1 covert skins.
This collection is exclusive to players who have activated an Operation Broken Fang Premium Pass. A random skin from this collection can be purchased from the Operation Broken Fang store within the CS:GO game client for 4 stars.
The Ancient Collection is rumoured to return in a Souvenir Package in the future with the recent addition of Ancient to the Active Duty Map pool used in CS:GO majors.