Sure, the deities that I consider Greyhawk deities are the those that
1) Were created by Gary Gygax both in Dragon Magazine and other sources (e.g., modules)
2) were from the non-human deities articles by Roger E. Moore from Dragon Magazines 58-63
3) the Suel deities by Len Lakofka in Dragon Magazine 86-90 provided that the Suel were found on Greyhawk in 1e (I no longer have my 1e Greyhawk stuff so I can't recall if they were or not).
New deities added by authors after Gygax left are not Greyhawk deities as far as I am concerned. I might find the articles interesting reading, but in my mind they are not Greyhawk.