Yes there are.
I've posted a list twice but the mods keep deleting it.
Keith Bennett.
Genette Tate.
Cheryl Grimmer.
And you’re completely wrong about the last case
In the 2000s, New South Wales Police Minister Michael Gallagher stated that it is entirely possible that both Cheryl and her kidnapper are dead but expressed hope that someone may know the truth. He also theorised that Cheryl may be alive and free and encouraged anybody who believes they may be her to come forward.[12] One of Cheryl's characteristics that was cited as a possible identifier was a belly button which protruded one centimetre due to a medical condition, which may or may not have been corrected by surgery.[13] In 2008 a woman believed that she might be Cheryl but, after submitting a swab taken from her inside cheek, proved not to be a match to Cheryl's DNA.[16]
In May 2011, a coroner formally ruled that Cheryl had died shortly after going missing due to an undetermined cause and recommended that police reopen the investigation—
Carole Grimmer stated that she believed her daughter was still alive.