Hair Volume Base / Hair Puff Insert: These are physical foam inserts, often shaped like a bump or donut, that you place under sections of your hair to create volume and a "poof" effect without excessive teasing. They act as a foundation for a voluminous hairstyle.

Hairline Powder Puff / Hair Makeup Cushion: These are cosmetic products, usually a powder or a liquid soaked into a cushion and applied with a puff, designed to fill in thinning hairlines, receding areas, or bald spots. They "found" the hair by adding color and thickness illusion. "The Face Shop Quick Hair Puff" is a well-known example of this.

Hair Mousse / Volumizing Foam (less common to be called "foundation"): While not typically called "foam foundation," hair mousses are foam products that provide volume, hold, and body to the hair, acting as a foundation for styling, especially for thin or fine hair.