I see some people have a special avatar that is not black and white. I want one too!

It's possible to unlock golden avatars in the shop which allows you to find them in the avatar section. There's also Gold Avatar Tokens which can be exchanged to request your avatar be turned gold, though requests can be denied.

Gilded avatars require the following:

1. That the Level 2 Avatar feature has been unlocked in the MD Shop

2. That the cost of gilding has been provided - most commonly, a Gilded Avatar Token

3. That the player possesses the monochrome version of the avatar in question (unless it is purchased as a gift for another, who possesses the monochrome version)
4. That the artwork can be gilded and uploaded.

At present, I (Aia) am able to gild existing avatar artwork, but Mur or Chewett will need to upload them to replace the existing monochrome version.