Tools need to change 93 Camry 4-cylinder valve cover gasket?

You will need a 30mm socket or wrench. First, pull straight up on the 4 rubber spark plug seats (the things with wires running out of them). Warning, if these wires are older they may break off while you are pulling on them, leaving part of the connection down the tube that the spark plugs are in. Use a long nosed needle nose pliers to remove the connection IF the wire seats break off. You do not need to remove the spark plugs.

After getting the 4 rubber spark wires out of the way, use a 30mm socket or wrench to remove the 4 nuts. Loosen a small amount at a time on each nut, but from the outside 2 then inner, to avoid damaging the threads and having a tremendous problem on your hands. Disconnect the 2 rubber hoses on the right, and pull the plastic unit on the left side up and out of the way carefully.