Tuned percussion
Mallet instruments are struck with sticks or soft mallets: marimba and xylophone with wooden bars, vibraphone and glockenspiel with metal ones, plus the hand-plucked kalimba. Their sounds are pitched and percussive, with a clear attack and a natural decay, which makes them work both as melody and rhythm.
Getting a playable instrument
Because each bar is a separate note, mallet instruments are easy to multisample, and several free orchestral and percussion libraries include them. Map the notes across a sampler, with two or three velocity layers if available; soft and hard strikes sound quite different. Repeated notes sound more natural if you alternate between two samples of the same pitch.
Tropical house, pop, ambient and game soundtracks use mallets constantly. Licences on the free libraries are often open, and each card shows the verdict.