If you are just doing the one side, a flat head screwdriver, 8 & 10mm deep well sockets, extensions, ratchet, and a spark plug socket.
However, the wiring channel behind the engine (bolted onto the 2 stud bolts on the back of the valve cover) is easiest to remove if you remove the 2 nuts securing it from each valve cover. It is a pain to lift it off the studs with only one side removed.
And to reiterate what I said before - if you have an oil leak on the drivers side, imagine what the passenger side looks like?