I don't have any colors to suggest but I do have two fonts to recommend.
Comic Code is a hand drawn monospaced font that invokes the feeling of Comic Sans without looking bad on modern monitors. I love it. The downside is that it isn't free, but if you're interested,
These two fonts just make things feel a little more human and whimsical in a way I can't fully explain and I love them.
Also, about color themes, never let anyone make fun of you for using a light theme. Sometimes they're better. It's not so simple as dark or light, some tools have awful light themes or awful dark themes.
Just some more font suggestions, these are not monospaced but just interesting fonts:
Input is a font that can be either monospaced or proportional, you can customize it. In the magical future where Elastic Tabstops catch on this font would be perfect.
I Like Input Sans for programming. iA Writer Quattro is similar to that. Now, I use for programming Recursive, a variable font with variable monospacedness among others. It has a configurator where all axes and features can be fixed for better compatibility.