In the Vetcove navigation bar at the top of the page, there is a button aptly named Lists. Click it to view all Lists you've currently saved on Vetcove. Each existing List will be displayed in the main pane on the page, and will also be listed on the left-hand column for easy access.
Vetcove has already provided you with three default Lists; "Previously Purchased", "Free Products", and "Resellable Products." These three Lists are dynamic, meaning they are updated automatically by Vetcove as products match. The custom Lists you create, however, can only be updated by you.