Inhumanoids/YMMV

Complete Monster: Metlar, D'Compose, and Blackthorne Shore all qualify for this.
Genius Bonus: The three Inhumanoids represent all three of the scientific "kingdoms", and these three kingdoms arguably help define the Inhumanoids' respective roles.

Mineral: Metlar. Since the planet itself is made of various mineral substances, it makes sense that he's the leader.
Animal: D'Compose. Quite a few animal species are at least somewhat intelligent, so it makes sense that he's intelligent as well, making him Metlar's Dragon.
Vegetable: Tendril. No plant species are known to have any intelligence as we understand it. In fact, the term "vegetable" is often used to describe a person whose higher brain functions have stopped. It wouldn't make sense for Tendril not to be a Brute.

High Octane Nightmare Fuel: A source brimming with it. Between the horrifying transformations and vicious monsters, it's a surprise they let it air on the kid's channel without controversy.
- One episode ended with a particular eldritch horror that hatched from an egg and then grew by eating the eggs containing his unhatched siblings. And even eating some of his hatched siblings. When fully grown in the next episode, he had a see-thru stomach. He swallowed an Earth Corps guy, who escaped by drilling a hole in the stomach wall and oozing out along with all the other bile. *shudder*
Needs More Love: This show is a very overlooked series that is in many ways ahead of its time.
What Do You Mean It's for Kids?: It is, despite being violent and dark.
- Particularly any episode focused on D'Compose's signature touch of undeath.