I've heard the occasional "Delta."
However, I use "David" myself because I don't know the "officially accepted" terms for each letter, and simply don't care because using that has absolutely no benefit over using something like "David" since the only purpose is communicating the letter, and these do it equally well.
Cheers.
Actually there is a very well established benefit of using the NATO phonetic alphabet: none of the codewords are easily confused. And if you actually know the entire alphabet you will more easily identify the codewords. D as in David is a pretty bad example, but I sometimes cannot understand the nonstandard codewords chosen by agents.
I am reminded of this Archer clip:
https://www.youtube.com/watch?v=_K_WmV50e7c&t=1m54s
