There are many fan made anime, but the most aren't translated, voiced and hard to find.
Also they are mostly just one episode and you will never hear from a second again.
My image is from the anime "Fantasy Kaleidoscope". The most famous one, I guess.
With flash you mean for sure "Walfas" animation.
There are also "animated" doujinshi comics/manga like "Osana Reimu" and "Koishi Komeiji's Heart Throbbing Adventure".