I only remember some desings, like for Tenna, Chapter 3 Secret Boss, Dess (or well named Amber for a strange reason in the Dark World), Chapter 4 Secret Boss, Chapter 4 Side Antagonist and some Areas.

Tenna: a Character that is blue like King and Queen, that has the tipical Gameshow clothes, with a smile and you can't see the eyes because they where black, like how King and Queen haves it.

He has a similar personality as Mettaton.

Chapter 3 Secret Boss: An Asriel PC Darkner that was a kind to the Fun Gang, but some times, he becomes crazy for some seconds saying nonsense, he will be in your team if you agree to help him to find something important.

He thinks that Ralsei is Asriel, that finally came home again, that's why he follows you and the Fun Gang.

Sadly I can't remember more of his desing

I couldn't see the Super Boss desing, because i waked up before seeing it. (for some reason I started Chapter 4 without making the Secret Boss fight, so I came back to make it)

Dess (Amber): You encounter Dess searching for her sister in some part in Chapter 3, she acts suspicious around the Fun Gang, and more close to Kris.

Amber is the name she tells you when she introduces to the Fun Gang. making as she is a Darkner.

Dess is the Knight in there and that's why she was in the Dark World because she was wondering who opened a dark fountain.

Chapter 4 Secret Boss: I don't know too much about this, because I barely saw something about this, but the Friend thing that you see in Queen's Basement is the Secret boss, you can see him too before the Secret Boss fight with the Asriel PC Darkner, dissapearing very fast when you see them.

You encounter them with the Fun Gang, and Susie send a Rude Buster tio them, revealing a strange Darkner with a Smile and with two colors in his eyes.

Chapter 4 Side Antagonist: some strange Darkners that seemed where themed for a Papyrus & Sans Home Dark World.

Some Areas: For Chapter 3 a City where you can see different channels from TV, A strange area themed into the stairs of the Dreemurr's House where you encounter the Secret Boss in his normal form, a Cooking show area, an area in the city themed into a Mafia program where you meet Rook (The leader of the Shadowmen).

Well just that, bye!