Ancient vessels are a fairly humorous collectible item from Horizon Zero Dawn. They are essentially coffee mugs, but the people in the game seem to regard them as some kind of ritual container. A lot of the dialog you get from collectors about them can be quite funny. Most of the time you will find Ancient Vessels around derelict ancient cities and buildings. Piles of scrap on the ground can often contain one if you notice that the inventory item has a purple icon above it.
Ancient Vessels Collectible Guide
There are a total of 12 Ancient Vessels to collect in Horizon Zero Dawn. They are all fairly easy to locate and hard to miss if you walk past one. The video guide below will show you the locations of them all, but you can also use a map to find them. There aren’t that many, so this will be a quick one to uncover.