After Toolkit > Animators > Flash Once
Make layers flash in After Effects
Make your elements flash in a sequence.Flash Once briefly boosts your layers' brightness from marker to marker.
Flash Once - Quickstart Guide
Open your After Toolkit, select your layers, and click on Flash Once.Flash Duration is the length of the flash effect from your Flash in marker to your Flash out marker.
Flash Delay is only relevant when multiple layers are selected. It offsets each layer's markers by the duration you enter.
Flash Intensity sets the brightness of the effect.
Keep in mind that the Flash effect will be starting from the timeline cursor current position, in the layer order of your selection.
Once you hit OK, you can edit each setting for each individual layer in the Effect Controls Panel.
Layer markers are automatically generated, allowing you to adjust the in-point and out-point of each animation.
The script can be applied multiple times to the same layer. When you apply multiple consecutive instances, each of them will get their own in and out markers, and their own settings control panel.
Everytime you apply custom settings, they are saved for the next time you use it again. Reset to default values will revert to original settings, before you ran it for the first time.
To cleanly remove this script, select your layers, click on the script's button again, and click on Remove from layers at the bottom of the window.
This button will appear only if the selected layers have this script applied to them.