Mind Workers populate nearly every aspect of Riley's mind. They tend to the day to day necessities of keeping things up and running. They appear as various sized and colored gum drop like globs with faces, arms and legs. Many have some kind of hair and/or facial hair.
It's possible they are allusions jelly beans.
Here are a few of the prominently featured Mind Workers.
The forgetters removing faded memories.
The operator of the imaginary boy friend generator.
The engineers who drive the Train of Thought.
Some of the crew behind the scenes at Dream Productions.
Security or Subconscious Guards.
Workers putting the finishing touches on the new control panel.