Light Leaks, at least “real ones” are created when light enters the camera in an unexpected way. With film, this could happen if you opened the camera body and exposed some of the film. With digital cameras we can do interesting things with lights that are out of focus or by removing the lens, and other types of non-traditional exposures.
Today, light leaks are used creatively to add some extra emotional impact to a scene or,
NoFilmSchool did a tutorial on how to create your own light leaks, which I think is worth checking out to come up with your own.
Here are some links to some of my favorite free light leaks
If you have found some cool light leaks, film burns, or similar assets, please let us know in the comments.