In anime, there is often an object or character that has a moment to shine and in that moment, there is usually a glint of sorts to show it's newness or fanciness. In the olden days, they used to draw a 4-point-star on the cells themselves, but these days, digital techniques, like this one, does sometimes get used instead, because time.
A very plug-n-play effect, this should simply get added to your setup and your glint will appear - and already animated!
For a soften effect, mix the clear result with a well blurred version and you'll have that too. For outlines, there are many options in blender.
To make the effect more legible for viewers, I added something I've never seen done and that is a clarity mask. This uses the same mask that is used to define the area of glinting, and inverts it, to clear out the most central parts of the masked object. This means if it's a person or object that's used, you'll still be able to see what it is, without issue. If you prefer it not be there, there is an influence factor to remove it.
NOTE - If you want an image full of glint, for whatever reason - remove the mask input and set the clarity mask to 0. This was built in EEVEE, but will work in Cycles as well.
If you're like me and you prefer the more traditional 4-point-star in yours, I invite you to check out my CGTrader - where you can get this one and that one as a package deal with added features: https://www.cgtrader.com/marius-oberholster
Seriously, have fun with this one! It was fun to make and I hope adds that little extra something to your renders as well!