Upvote: https://github.com/grafana/grafana/issues/18041 and add any additional comments and context there. In addition to making the light/dark themes more accessible, I think we should add an additional high contrast one.
I'm also colorblind and a heavy Grafana user but I haven't had much difficulty reading dashboards. What are you having trouble with? The most trouble I've had is colors of multiple lines on a chart being too similar but being able to use the mouse to select a line and see what the line is and its value helps there.
The default palette is definitely a challenge, since it has pretty low contrast and Grafana's defaults use a lot of thin lines.
I especially have trouble matching colors in a legend with the drawn objects in the graph. The best help has been the hover panel, but it's unsorted by default and the highlight contrast on the panel for hovering over a line is pretty dim.
As a color blind user, I find it difficult to read the dashboards created by others. How can I help any efforts to increase Grafana's accessibility?