I'd like to suggest "Gudjal" as an alternative name for Warungu. I found this language spelled as "Gudjal" while doing research and wanted to find its ISO 639-3 code; I was surprised to be unable to use Ethnologue to find it, since the Ethnologue search does not include the term "Gudjal". You have "Gudjala" included already, but not "Gudjal".
A few sources that include "Gudjal" as a primary name, alternative name and/or dialect name:
Dixon, Robert M. W. Australian Languages: Their Nature and Development. Cambridge University Press, 2002.
Holmer, N. Notes on Some Queensland Languages. Canberra: Australian National University, 1988.
Santos, William. Gudjal Language Pocket Dictionary. Collingwood, Victoria: Black Ink Press, 2006.
Santos, William. My Country in Gudjal Language. Collingwood, Victoria: Black Ink Press, 2006. (+ various other books by this author)
Some of these sources classify Gudjal/Gudjala as a dialect of Warungu or as a separate language closely related to Warungu; nevertheless, these sources seem to agree that the name "Gudjal" is a variant of the name "Gudjala" which you already have listed in the entry for Warungu [wrg]. So, without getting into the question of classification as a language or dialect, my suggestion is simply to add the name "Gudjal" alongside "Gudjala" to make it easier to find when searching.