A couple quick 2-3 hour sketches of fantasy characters I did before GDC: they are supposed to be able to work for video games as well as trading cards. Left: a succubus preparing a dark spell Right: Commander of a royal army.
I feel like it would be more beneficial to spend 2-3 hours coming up with about 10-15 different versions of each character, not rendered, just pencil sketches if you want a diverse array of characters. Not just different outfits, but different attitudes, backgrounds, poses, and auras. When it comes to Fantasy (or any genre for that matter), many of the producers in video games and trading cards want to see all the possibilities of the characters before they make a decision to render and implement that character into the pipeline. The more you can show in a short amount of time, the more likely they are to want you as their artist. Explore the character many many times on paper no matter how ugly it is and expose it to the world so the producers can decide if they like it or not. They are, after all, the people funding the careers of artists. I learned that at GDC this year from major producers. GL.