Firefox and Chrome now support the caret-color CSS property. I think it would be a nice touch to paint it blue, for example (I tweaked my global.css with caret-color: #36c, a color from M82, and boy, it looks ace!).
More info on the new feature: https://blogs.igalia.com/mrego/2017/01/09/coloring-the-insertion-caret/
I think it would be a great addition even if at the present time there is limited browser support, because it fits the philosophy of “progressive enhancement” IMO.