Goldie

Goldie is a ruler application that gives you the Golden Ratio without the math. The utility adapts to the background color while applying an overlay ruler on your screen.

You can switch between Goldie rulers with your preferred shortcut. You can flip or lock in place with the click of a button. Goldie uses commands that are native to macOS, but you can personalize to create custom shortcuts for showing rulers, or toggling between ruler themes.