I love being able to customize the color scheme of DrRacket.
I am partial to the Dracula scheme which can be installed from the packages list, with some slight modifications, because I really like the dracula-orange and dracula-green, which do not feature very heavily in the scheme by default:
As you can see, below, this makes artefacts like splicing operators stand out, nicely, and when I am using at-exp mode, the orange is delightful--almost reminds me of those gorgeous monochrome CRT screens with the orange or green hues.