There are four distinct instrument types with specific powers.

Percussion instruments such as the xylophone, djembe, rattle, and all other drums are ruled by the earth element. They can be used to increase money, find a job and gain fertility.

Wind instruments such as flute and recorder are ruled by the air element. These can be used to increase visualization or mental powers, discover ancient wisdom or knowledge, etc

Fire dominates string instruments such as harp, guitar, lyre and sitar. These instruments can be used in rituals dealingwith sexuality, health and bodily strength, passion and willpower, destruction of harmful habits, etc. They are also great to use to purify an area for ritual or other purposes.

Resonant metals such as bowls, cymbol, gong, etc. are dominated by the Water element. These instruments are typically associated with healing, friendship, fertility, compassion, happiness, etc.

These are just a few examples of instruments and associated elements, I'll go into a bit more detail when I'm more awake. If you've got any questions feel free to ask them!