Although it's collection is more work from the past than the present, you will find much avant garde video work at ubuweb. posted by extrabox at 8:50 PM on July 17 [1 favorite has favorites]
Not totally sure what you're looking for specifically, what time period (or does that matter?). I can't think of specific sites that compile videos. Lots of cities have fringe festivals each year, which might have some interesting performances. I don't know a lot, but here are a few quick links off of YouTube since you said that might work:
posted by extrabox at 8:50 PM on July 17 [1 favorite has favorites]