Ath'kethin
Elder Thing
Historically, elf subrace = money printer, IIRC. And I suppose we could view subrace = culture or subculture, but I feel that idea breaks down a bit with humans at least.Isn't that what substitutes for cultures in 5e? I realize this is all in flux with lineages and such, but was basically my understanding: subrace = different culture
Also, come to think of it, it breaks down with Krynnish elves, where two of the primary nations (Qualinesti and Silvanesti) are explicitly called out as High Elves.