Ask the dentist!
I remember when I was a kid a really special treat was bubblegum flavoured toothpaste, which was just from the supermarket at the time. I remember basically being a celebrity when I had it at grade 5 camp. I'm not sure if it's still sold.
Other than that, try health food shops - though I have a sneaking suspicion that the non-flouride-or-any-other-chemical toothpaste that my grandmother uses is clove flavoured, which might not be to your daughter's taste either.
FWIW, I generally hate mint flavoured things because they taste like toothpaste. But I am happy to brush my teeth with mint flavoured toothpaste. Your daughter is perfectly normal to me!