Welcome to the Airtable community!
If you want to transfer a workspace to someone else, you can add them to the workspace as an “Owner” and then remove yourself.
However, that person will then up having (and paying for) two Pro workspaces. Of course, the new owner could then drag all the bases to one pro workspace and then delete the extra one.
If you want to transfer some (but not all) bases to another person’s existing Pro workspace (so they don’t have to pay for two workspaces), I like to use this technique: