Для справки, по каким "критериям" на сайте устанавливается этот тег (ранее именуемый "безумие"):
Experimental fiction which shunned conventional storytelling at the time it was created. These stories often invoke unsettled feelings because they reject traditional ways in which we prefer to view (or escape from) the world. Narrative is avant garde works is often of higher importance than the content.
Deconstructions often fall into this genre. Note that simply being darker, edgier, or cynical doesn't mean the work is avant garde.
myanimelist.net/anime/genre/5/Avant_Garde