Microbiology Question about staining.

The question I am looking to answer is:
"List 3 different types of stains used to help visualize cells."

This is what I know about staining:

Stains:
1.)Simple: Used to highlight microorganisms to determine cellular shapes/arrangements.

2.)Differential: Used to distinguish different kinds of bacteria

• A.) Gram: Gram + and Gram -
• B.)Acid Fast: Used to distinguish Mycobacterium.

3.)Special: Used to color and isolate various structures, such as capsules, endospores, and flagella.

• A.) Negative: Used to demonstrate the presence of capsules.
• B.) Endospore: Used to detect the presence of endospores in bacteria.
• C.) Flagella: Used to demonstrate the presence of flagella.

Would the answer be Simple, Differential and Special?- but are those just categories and not stains? Or would it just be any combination of 3 stains: like simple. gram, and acid fast?

Thanks.