I’m digging these! Your shading is looking great and the characters’ outfit designs and colors really work well.
Leetha is probably my favorite, the background with the busted wall is a super cool idea. Also, the designs on her cuirass are great, I love the color choice.
If you’re looking to play around with colors even more, one thing I always recommend is trying out different line colors. It can work especially well if the design has a lot of items with thick outlines, which will stick out less if the line colors are less dark. For instance, I might use a very dark brown instead of black for body items, a very very dark blue for black hair, and a dark grey for metal items. If that sounds like too much work, no worries, these are looking really good as they are.