What instruments are mostly closely related?

Instruments that are most closely related typically belong to the same family, such as string instruments (like the violin and viola), woodwinds (like the Clarinet and Saxophone), or brass instruments (like the trumpet and Trombone). These instruments share similar playing techniques, construction materials, and acoustic properties. For example, the guitar and the lute are both string instruments that use plucking or strumming techniques, while the flute and the piccolo are both woodwinds that produce sound through the same principle of air vibration.