I used to have a program that had several test patterns in a few VGA modes including text mode that was very helpful for calibrating the OSSC I'm using to digitize the VGA output of my retro computers. I can't seem to find it anymore; I was pretty sure I got it from Vogons, but searching yields nothing. I recall the exe being something somewhat descriptive, like "monitor.exe", it brought a menu and there you could get some different types of patterns, and it was very useful for stuff like phase adjusting.

Anyway, since I cannot find the tool, I might as well ask for general suggestions in screen calibration software for DOS.