The next Toad beta, to be released Monday, November 8th, will have Dark Mode!
There are actually about 20 different color themes of varying darknesses.
If you are the type who works in a dark office with no lights except from your monitor and maybe a backlit keyboard, you'll probably like the "Glossy" style:
Or the "Cobalt XEMedia" style:
"Charcoal Dark Slate" is a little less dark:
Here's an example of a lighter one. This is "Sapphire Kamri"
They're set here, under Main Menu -> View -> Styles