need better white-background color schemes.
You have great black-background themes, but the only white-background theme that's usable is 'eclipse' (lang=JS-jsx). You cannot take a black-bg theme and just change the background - the result is a barely-visible theme, because all the other colors start out very bright.
There's little contrast against a white bg. All 3 of the numbers should be 0 to b, and at least one should be zero, otherwise it's not dark enough. In Base-16, there's colors #f4bf75, and #90a959, basically pastel tint colors. Worst is icecoder, where a color is #eee - what a poor color against a bg that's #fff! It's barely visible.
Try colors like #bb0 #770 #0b0 #b80 #0b8 #b60 #60b