Cover Characteristics: Black, White, & Green Book Covers

I've been doing these color themed cover posts every so often, and, you might not have noticed, but I've actually been doing them in order of the rainbow. I've already done red, orange, and yellow, so today we've reached green! Green was significantly harder than I thought it'd be. I mean, it's green! You'd think that wouldn't be hard to find. I also ran into the issue of such varying shades...