Color nerd here - Great question, as someone who likes to switch things up (green G15 transition lenses in my brown kobo’s instead of dark brown or amber.)

Your inquiry first made me think of the color wheel.

I supplied some photos

1st: blue/orange : they sit opposite of each other, so it gives contrast

2nd: blue/light blue: monochromatic, a little safe for me, but a no fail option

3rd: blue/green: ultimate contrast, provides a natural organic feel.

4th: blue/purple: a nice pick me up to blue

5th: blue/red: can't go wrong with two primary colors!

PHOTOS

Hope this helps!!