I used to use molokai (dark, fairly high contrast); a few years ago I decided to build a new minimal, light, high contrast one from scratch, which I called “bland”, inspired by the printed code of yesteryear. Paired with Triplicate, the only true serif monospace font that I can think of (I have a vague feeling I found one other once, but can’t think what it was). Black text, white background, keywords bold, comments italic, that was it. I tried that for a few days and decided I liked it, but did want strings and comments distinguished, so I made strings red, comments green, numbers blue. Over time then I’ve added a small number of other cases for specific languages and constructs, but it’s stayed very minimal compared with what almost everyone’s doing.
Well, I deliberately tried it for a couple of weeks, then went back to molokai for a week before I broke and went back to bland because I found it just so much better.
It’s what I use in code blocks on my website, though with light grey backgrounds rather than white. See https://chrismorgan.info/blog/rust-fizzbuzz/ for an example.
It was a couple of years before I even bothered to make a dark variant of the theme, for the occasional low-light situation where dark actually works better, and because I wanted to have a dark mode on my website. I almost never use bland-dark.