How to make levers
Gear lever weel-tips
Gear lever mecano
Here are a few pictures from gear lever systems. You have different types.
Flaps lever & interfacing
Magnetic sensor for easy interfacing the flaps lever.
Alternatives to gearwheels
Friction
Control cable connectors
A "terminal block" that is cheap and easy to find on most electronic stores is of course very useful in keeping tidy connections in the cockpit:
But it can serve another purpose too. If you remove the screws and take out the metal piece from inside, and re-insert the screws without the plastic casing, it becomes a very useful tool to connect cables and wires together in pushrod / control cable uses:
On the above throttle setup it is used to connect bicycle brake cable wire into solid metal rod that has the "z-bend" to attach to the throttle lever. Normally it is hard to connect cable to something else without welding equipment, but those screws hold tight enough. And the terminal blocks are available on several sizes.