We have the lever, pulley, inclined plane, wedge, wheel and axel, and and screw. Could a pendulum work, too?

In what regards? Is the pendulum meant to perform work? As in a grandfather clock? Many things pendulate, but perform no work, consider tree branches as they blow in the wind. I don't see pendulums as an effective means to transmit force effectively enough to be considered a simple machine. However, a hill could be considered an inclined plane and it simply exists naturally so I dont know. Interesting question. What are your thoughts?

If a wheel qualifies, definitely.

Yes

A pendulum does not help in the transfer of forces by altering the distance of it in any real way.