Any creative group active in the innovation and application of new concepts and techniques in a given field (especially in the arts) WordNet 3.0 & Open English WordNet

In the arts and in literature, the term avant-garde identifies a genre of art, an experimental work of art, and the experimental artist who created the work of art, which usually is aesthetically innovative, whilst initially being ideologically unacceptable to the artistic Establishment of the time. Wikipedia

Works that are experimental or innovative Wikidata

A creative group active in the innovation and application of new concepts and techniques in a given field, especially in the arts. OmegaWiki

Any group of people who invent or promote new techniques or concepts, especially in the arts. Wiktionary