Tetum is now an official language of Timor Leste. It has no 639 code.

Seselwa, a French Creole, is an official language of the Seychelles.
It has no 639 code.

Information I got from "Pays et capitales du monde", a publication of
Conseil National de l'Information Géographique, which I received
while at the 3166 meetings in Paris earlier this month.

This report noted other languages which had no codes, but it turns
out that they only had 3-letter codes, and the compilers were only
looking at 639-1.

Tigrinya has ti which the investigators must have missed.
Haitian Creole was listed as having no code.
Palauan has pau in 639-2
Tok Pisin has tpi in 639-2
Michael Everson * * Everson Typography *  *