Comment on Brush Pack 2014 by ProxyGreen

It's called chromatic aberration and you can do it by generating split layers from the RGB color channels and then setting them off. ProxyGreen most likely has a script for that because he uses this technique a lot.
Here's a tutorial for Photoshop and one for GIMP (even though it's in French, you can see what the dude is doing), if you wanna give that technique a try.