As Hirnie says, gear lever, brakes, slats/flaps, throttles, radios, autopilot and engine instruments arenot duplicated but they're in the center anyway.
Some aircraft (mostly smaller ones) only have the tiller on the left side. One example is the DC-9. That's why the left hand pilot on the DC-9 always steers. If he is not flying that leg, he will call eighty knots and release the tiller at that point during takeoff. He will also take over steering of the nosewheel under eighty knots during landing.
"There are no stupid questions, but there are a lot of inquisitive idiots."