GLARED is a REAL-TIME LIGHT LEAKS GENERATOR that works directly in the VIEWPORT of Blender both in Cycles and Eevee. Really easy to use. 

Glared is a useful add-on for generating the light effects present in many film shots (such as Glow, Ghosts, and Streaks) using the scene you are working on as a starting point. It can be used in real-time on the 3D scene or on photos or videos. There is a Threshold value that determines which values to use to activate Glared’s filters. In addition, Glared creates Chromatic Aberration, Vignette, and Sharpening effects.

Glared works in real-time directly in the 3D viewport

Glared on/off

Chromatic Aberration FX

Ghosts Intensity

Ghosts Scale

Glow Intensity

Streaks Horizontal Length

Streaks Color

Vignette FX

And you will find more controls into the add-on.

FEATURES

You can find more details on the official website.

* The 3D scenes of this presentation come from https://www.blender.org/download/demo-files/
and they have been used only for testing purposes. The video footages come from https://pixabay.com. Credits go to the authors.