If indeed you are using standard Ubuntu, and are referring to the workspace selector that appears on the right of the screen when you click the Activities button or press the Super key, then most probably you will like the Gnome Shell extension Workspaces to Dock. In first instance, this extension was designed to show the workspace selector as a dock on the desktop, similar as how the popular extension Dash to Dock (and also the Ubuntu Dock) turn the dash into a dock on the workspace.
To suit your preferences, you can configure the Workspaces dock to be on the left side of the screen. You will then need to move the Dock to the right or the bottom of the screen. However, Workspaces to Dock includes also functionality of the Dock, so you could eliminate the Dock and control both workspaces and applications from a single dock to the left of the screen. There are many options to control the feel, look and behaviour of the dock.