What’s wrong with #ffffff?
Somehow when we had only 16 colours to work with we didn’t have the worst of the designer-brain “grey on marginally different grey” eyestrain factories. High-enough contrast for accessinility was essentially guaranteed. And you could go even more restrictive for laptops with early washed out LCDs and only-shades-of-red plasma screens.
I recall in the CRT era, yellow-on-blue was considered the most comfortable.
I can recall always typing “COLOR 15, 1, 1:WIDTH 40” to switch from light-grey-on-black to white-on-blue when I went to program my 386, much easier to read.
Not sure how those studies map to the different properties of LCD screens.