Re-posting a very old list of ideas to kickstart your inspiration that *skulldog (https://www.deviantart.com/skulldog) posted years ago. Still useful and relevant if you ask me.
100 design themes.
Words consist of adjectives that describe both physical and personality traits, others are color combinations, and a few are simple open ended names/titles. For each of these, the challenge is to design a character, creature, race, costume design, or whatever else strikes your fancy. Work in order, pick and choose, the idea is to have fun and expand your creature design work.
3. Light yellow / Gray / Red
7. Dark Green / Iv