They shipped Outcasters and just today Journey to Savage Planet. Admittedly I believe both those games may have been in development before the studios were acquired, but they are both first party exclusive Stadia games.
Journey to Savage Planet is neither first party nor exclusive. It has Switch and PS4 ports. You'd be on the mark for Outcasters though.
Journey to Savage Planet was made by the studio they had acquired (Typhoon studios) which they are now letting go again. You are right that it's not exclusive, though I still think it would count as first party (or maybe second party?).