These three themes have something in common besides being lovely: each is tiny. Eleven ocean names, twenty from music, eleven royal titles. Other sites turn each into its own list of fifty by inventing the rest; here they share an article and the counts are stated.
The tags are strict for the same reason the lists are short. A name is filed under ocean because it names something in the sea, not because it sounds coastal.
They will grow
Not by invention. They grow when a source lands that can classify more names — the tags come from a lexicon that records what each name refers to, and every addition has to name its referent.
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.