While it may not be online as such, the list SHOULD be summed up by perusing the legals pages for Deities & Demigods, and Faiths & Pantheons. However, I note that WotC failed to put a trademark listing in Deities & Demigods, and I wouldn't be surprised if F&P is similar...
Of the "D&D Pantheon" as listed in Deities and Demigods, all names are, as far as I can tell, original to TSR/WotC except Tiamat and possibly Bahamut. The four unusual deities (Taiia, Elishar, Toldoth, Dennari) at the end of the book are also WotC's. The classical pantheons in the rest of the book are not a problem.
The Forgotten Realms deities in Faiths & Pantheons are, as previously noted, a mishmash. You can be pretty safe by treating the non-human pantheons as WotC's.