On mac I’ve used one called “Red Lines Tool” but it hasn’t been updated in 2 years and is a little finicky at times. There’s another that is similar (but newer) that I’ve just downloaded to test called “SmartGuide - Screen Guide”.
EDIT: as a follow up, I really like “Smart Guide”. It’s very simple to use, and the lines you can place on screen are selectable when you are in other programs. (This can be a pro or a con. I just know in my “red lines” tool they were totally inert unless you changed back to that program, whereas with smart guide you can click on it, and drag it (although you then have to make Dorico the program in “focus” after that. But it’s very svelte and simple, and it only costs $2.99.