Avant Garde to me is anything that isn't created for the mainstream/capitalistic society. It is usually created out of someone's own self interest and paid for out of pocket or small donations. Because it's not created with the general public's interest in mind, the films tend to be out of the ordinary or abstract.
I have not yet decided what my film will be about for sure, but this is one of the ideas that I've thought out so far: the plot will be obscure and comedic. It will take place in an alternate reality and include cultic/ritualist imagery. Coffee will be worshipped. I want the film to appear low-quality with layered imagery and very few colors. The people in the film will appear dirty and wear animal masks.
Although, I may not stick to the idea of a world where people worship and bathe in coffee, I still want the people in my film to wear animal masks, and I want the film to be low-quality, and have gritty, layered imagery.