My approach would be to look at pixel fonts
The problem you will have is that on a pixel font you can not controll diferent sizes, either you have for example a font of 10 px and that is it. You probably can not have it as other size.
But a cool work around would be to use Gimp, but to use a text editor. For example, Notepad++, and then configure your working font there. Settings > Style
I use a lot Verdana and it looks nice at 11px but counting the descendants will be around 16px then make a screen capture.
Another font that was designed for screen, before the sub-pixel era was Tahoma, and probably Calibri. Take a look at the Classical "Web safe" fonts.
If you can get your hands on a computer that runs Windows XP you can make faster tests, because it has not the Clear Type feature, so the text will be plain black on white.
Another good option is the System font. Look for it inside your "Font" folder. It is not a true type font. Is a pixel font actually. And has some pre-defined sizes that work well.