I can't seem to sell my ancient artifacts with merchants in horizon zero Dawn, they literally aren't present in my resource inventory yet it says I can't store more because I'm full, is there a way around this? It's quite frustrating 😒
If you are referring to the idols, and the cups, etc, they can only be sold to specific vendors. Studious Palas purchases the cups from you, Kudiv buys the Metal Flowers, and Cantarah purchases the Banuk Figures. All of these Merchants can be found in Meridian.
These special artefacts actually don't count towards your current inventory, however, that allows you to carry more resources. You can instead upgrade your inventory, or sell off some of your resources.