Thanks for your color flash, I'll try it. As for my flash transition collection, I think they all came bundled with pay packages. I have a bunch of them. Was hoping I could click on the inspector & it would tell me who made each one, no such luck. One of my favorites is called Film Flash, I use that one from time to time. There are others I haven't tried yet.
Couldn't you also just use a Fade to Color transition, set the color to whichever one you wanted, then speed up the fade to mimic a flash?
Here's a list of the flash transitions I have.
4 Panel Flash
4 Panel Flash Freeze
Color Flash
DH Light Flash
Exposure Flash
Film Flash
Flash (two variations from different manufacturers)
Flash Freeze
Flash Invert
Flash Invert Freeze
Flashback (not the kind of flash we're talking about here - but it shows in the search - it's the interesting liquifying effect when you dream nostalgically to way back when...)
and finally...
Horizontal Edgeflash
6 of these come from XEffects Tech
1 from Nattress Film Transitions
1 from Digital Heaven
2 from C2
Another 5 variations with set frame durations for slow or quick - from Luca's Light Kit (some of these are super annoying - like repeated flashing stroboscopic effects - perfect if your intent is to trigger epileptic seizures). But in their defense, Luca's have a multitude of adjustable parameters (too many to list)