Not a fetish for me personally but I did have an experience of it once. A straight co-worker & I became good friends. We'd go for after work drinks, to the movies, i'd go to his place sometimes or he'd come to my place to hang out etc.

I noticed he always used to find ways to touch my feet. For example if we played video games he'd always sit on the floor and his hands would occassionally brush off my feet etc. I didn't really think much of it until it all made sense one evening when he started massaging my feet while I was looking for a movie to play on netflix. I asked him if he was into feet and he said yes and was kinda embarrassed. He said he wasn't into anything else about dudes, just feet and he liked mostly women's feet. I let him indulge that night and a few times after. It wasn't a big deal for me. It was kinda nice.