After my teenage years it's been very rare for me to dig into a band deeply enough to learn anything about their members, so the easiest examples are all going to be women doing clean vocals, which is the one time you can (usually) explicitly tell the difference just by listening. Some of my favorite examples are Liv Kristine's work in Theatre of Tragedy, Tarja-era Nightwish, the first Stolen Babies album, and Sirenia's first two albums along with all of Tristania's discography pre-Rubicon.

I have two examples that immediately come to mind outside clean vocals:

Samantha Escarbe is the guitarist for Virgin Black and my understanding is she essentially splits the songwriting load with Rowan London. The Requiem stuff I still need to give more listens, but I think the first two albums are absolutely spectacular music. In "Museum of Iscariot" she does one of my favorite guitar solos I've ever heard.

Angela Gossow's vocals on Arch Enemy's "Wages of Sin" album are some of the absolute best in metal. I live for that shit. I never really got into anything else Arch Enemy did though.