If the basement is mostly brown and green, using some yellow would be good, since that's roughly between the brown and green on the color wheel. Then you can use some red accents throughout since that's across the color wheel from the green. So you could paint the stools red, with yellow seats, or do yellow stools with red seats. You could do some red pillows or artwork with red and yellow in it. Here's a link to a
color wheel that shows a lot of tints and shades so you can get an idea of what secondary or tertiary colors go together.
We got the stools. They’re lightly finished so I’m taking that off, then painting. I’ll take pictures when I get the chance. I’m going with the dark red and black, to be a real contrast in that room. We need something bright and interesting down there.