Redhead fetish refers to a sexual arousal by or sexual interest in those with red hair.
Kinkly explains Redhead Fetish
The redhead fetish is one of the more common fetishes. A redhead enthusiast might find themselves attracted to the contrast between the red hair and pale skin. The fetish may also stem from personal characteristics associated those who have red hair. Personality traits commonly attributed to redheads are a fiery disposition, aggressive, and sensual.