Sound Units
In UK your absolute best bet is 'Action Electronics' at 'Component Shop'.
They have a good selection of engine sound as well as honkers , pingers, tooters, bells and whistles🙉😁
In another category you can also find suitable RC switches. See attached links.
Cheers, Doug😎
PS The jargon book never turned up😭😠
https://www.componentshop.co.uk/action-electronics/other-sounds.html
https://www.componentshop.co.uk/action-electronics/engine-sounds.html
https://www.componentshop.co.uk/action-electronics/switches.html