Actually, Unity provides a few scripts such as the FPS controllers, camera script, and everything.
But I still prefer to make my own scripts.
Unity's made script is not a rigid body movement, so that means, there will be no physics involved (Only a transform translation.).
It also sometimes does not do what you required it to do.
(Such as controller change, footstep sound, camera-blocking-walls, torque movement, directional acceleration (Where the force comes out from, such as for my ship, it came from the two thruster at the back.), etc.)
Basically, you still can make games with Unity's scripts that they provided,
and you can even buy scripts from asset store if you have no Idea how to (But there is a great unity Q&A community out there, so why not just ask?), feel free to do so, but will not be what you "Seek", they are just an example by unity,
on how the you manipulate the "Character controller", Unity's event functions, etc.
They are there for you to "See/refer" from.
And you are to create from what they provided.
and 99% of the scripts you needed, aren't there in unity anyways.
(Since unity only provide movement scripts.)