1. Kantele: a Finnish stringed instrument similar to a zither.
2. Keyboard: a musical keyboard is a set of keys that control the pitch of a musical instrument. It can be found in various instruments such as pianos, organs, synthesizers, and more.
3. Kazoo: a simple musical instrument that produces a buzzing sound when hummed or sung into.
4. Kaval: a woodwind instrument from the Middle East and Eastern Europe. It's a type of flute.
5. Kharatal: a pair of wooden clappers used in Indian classical music.
6. Khene: a bamboo mouth organ from Laos and Thailand.
7. Kora: a West African stringed instrument with 21 strings.
8. Kroncong: a traditional Indonesian stringed instrument similar to a ukulele.
9. Kurtzweil: a brand of electronic musical instruments, particularly known for its digital pianos and synthesizers.