Elegance in a name is mostly rhythm: more syllables than average, soft consonants, a vowel at the end. Isabella, Seraphina, Aurelio. The site derives this from the letters, which is why it can be filtered at all.
Sound is measured; taste is not
This is a classification of how a name sounds, not a claim that it is beautiful — that judgement is yours and no dataset can make it. The distinction matters here because the neighbouring luxury tag is the one place this site comes closest to taste, and it says so on its own page.
Every count on this site is a tally of real registrations: pet licences and shelter intakes published as open data by New York, Seattle, Austin, Montgomery County, Cambridge, Zurich, Basel and three Australian councils. Popularity here is the average share a name holds across those registers, so a name common in a small city is not buried by one common in a large one. Nine of the eleven sources are North American, so read the ordering as naming in those places rather than worldwide.