This is my attempt at creating lens flares that are similar to those seen through an anamorphic lens. The 'Anamorphic Lens Flare' node group is the result, and it includes a number of settings for tweaking the flare to look however you would like it to - Subtle, or J.J. Abrams.

You can also tweak the individual elements of the flare:
Streaks (horizontal blurred, usually blue lines)
Stars (8 point star around each bright point of light)
Ghost (inverted reflections of each bright point of light)
Glare (bright blurred spot around each bright point of light)

Use this for still images or animations (it does take a rather long time to render, however.)

Instructions and descriptions of the settings are found in the blend file.

Have fun with it, and I hope it is useful!