The item "Yardlie Toothbrush Foam Cotton" appears to be a common way retailers describe a type of toothbrush marketed by the brand Yardlie Professional.
While "Foam Cotton" is not a standard dental term, the search results strongly suggest it is a descriptive term used to highlight the extreme softness and high density of the bristles on a specific line of their toothbrushes.
Yardlie sells several toothbrushes that fit this description:
Micro Nano Manual Toothbrush: This line is frequently promoted as having "ultra soft nano bristles" to prevent enamel damage and avoid bleeding on sensitive gums. The high density of these ultra-fine bristles is likely what inspires the "Foam" or "Cotton" comparison, as the bristle head feels very soft and dense like foam or cotton.
"Deep Clean" and "Soft Bristle" Toothbrushes: Other Yardlie products emphasize "soft bristles," a "deep clean," and sometimes mention an ability to "generate fine foam" when used with toothpaste, suggesting the bristle design is meant to create a gentle, rich lathering experience, which could be the source of the "Foam" part of the name.