lens flare

[Gary Hazen]

It looks like some of the end burn clips from Art beats library.
https://www.artbeats.com/collections/160?page=4
These are typically composited over footage using a luma matte.

OR

Light leaks effects from Luca Visual FX
https://www.lucavisualfx.com/

[Grinner Hester]

I didn’t see any lens flairs (and was glad). I did see some luma keys of a canned effect from artbeats. They become recognized as they are over used…. as in this video. You can create your own in Avid or in After effects by using various elements with glows and blurs. You can save em and compisite them as mentioned above or better yet, one-off them per project so they are always appropriate and unique.