The main coast road out of the city- towards Belem, catch the tube/tram line to Cais Do Sodre, and walk.
Along this part, are many “works of art ” the “big cat” is of special interest. Return to tube station and walk coastal path – many more to see.
Directly under the bridge is the MX building , where you will find not only street art , but many bars, and places to eat, the old building has been leased to many artists/designers.
Also , Bairro Alto part of the city has many more “works of art”.