I’ve used GuideGuide for half of my (illustrious) career at this point. It’s really the only plugin I use in Photoshop and Illustrator and i’m excited to know if I ever have the misfortune of having to learn yet another Adobe tool, GuideGuide will be there.
I use guides constantly in photoshop and GuideGuide has been a life saver. It enables you to create guides of any complexity, save sets of guides you've created, and use scripts to create them if you need to plan them out in advance. As an artist doing fine art in photoshop this has been invaluable. And support is terrific!
GridGuide is an invaluable tool. I use it regularly in my print work. It’s speed and simplicity of use streamline my workflow greatly. How this is not a standard feature with Adobe’s software beggars belief. Worth its weight in gold!
As a professional designer, this is the one paid plugin that is worth every single cent. It's the ultimate cheat code for people that live by the grid.