Question: <https://www.google.com/search?q=western+musical+instruments>

Will it be very few western musical instruments that can be played by human beings with one hand only?

Example : Mouth organ.

Answer: 
Bugles are one-handed. Trumpets, tenor and French horns would be playable to *some* extent. The pipe of a pipe and tabor! Flexatones are lovely things. I've seen virtuoso bass guitarists play whole pieces with one hand.

At [OHMI](https://www.ohmi.org.uk/instruments.html) (One handed musical Instruments) there are all kinds of instruments and *adapted* instruments. The one-handed clarinets and Chapman Sticks look good. They also have supports for the trumpet and trombone.
Three hole pipe. Usually used in conjunction with a drum to form the pipe and tabor, but the pipe part is a one-hander