Musical groups that don’t compose are generally keeping older traditions alive. Some musical groups are also known for evolving musical traditions by seeking out, and even commissioning works by living composers. Then there are other groups that reinvent the works of others, putting their own particular spin on the music. Whenever possible the links navigate to the home page for each group.
This is just a list to get you thinking and for further research. This only scratches the surface.
Kronos Quartet – a string quartet known for performing music of living musicians
The Fab Four – a Beattle tribute band
PTX – Pentatonix, a 5 member acapella group
Gregorian – a group which remakes song with a Gregorian Chant flavor
Celtic Women – A performing group that focuses on traditional Celtic music
Nexus Percussion – A percussion quartet that performs contemporary percussion compositions
Gamelan Semara Ratih – performing traditional Balinese music and dance
The Piano Guys – a duet that creates mashups with guest artists
Disney Live – All types of performances of Disney music for live performance at the parks and on tour