Not sure if call it a fetish.
It started with my wife (while dating) would always have me put on and take off her shoes for her. This would require me to kneel before her, whether she was sitting or standing. The foot that was bare and not being trended to would wiggle into my crotch.
My wife and I actually have the same size foot, I have small, narrow feet for a man, but also i'm 5'6 and she's 5'11, so her foot is perfectly proportional to her height. Her foot in it's own right is proportional, toes not stubby, but also not long. They are perfect.
To be honest, I never thought anything about feet before her, but constantly on my knees, holding her foot...I started to love kissing them and sucking on her toes (which she loves) and she'd constantly wiggle her toes in my crotch sitting across a table, at a restaurant or even her parent's table.
But one of the hottest things is to take high heels off a woman, one foot tucked in your crotch as she lifts her other leg, hiking up her dress, the lace top of her thigh high caressing your cheek as she puts her leg over your shoulder and pulls your face in her gates of heaven and makes you eat her pussy, fully dressed on your knees before her.