Clockwork could be #10 possibly, afterall it has been in development since 2020 (longer than Gears E-Day which seemed to start in 2021 after Coalition finished their work on the Gears 5 XS port and the Matrix UE5 Tech demo) and had gameplay footage ready Summer 2023, not in-engine, but actual gameplay clips in that reveal trailer. Could also be Contraband maybe, but alot depends on if it was fully rebooted or just partially rebooted. 

Edit: Oh yeah, we can't forget Project Mara, the original vision for that game was a 2 hour or so long experience set primarily in a single penthouse apartment, an apartment which was already fully modeled like 3 years ago. Maybe since then the game has been cancelled, or maybe the decision was made to expand it into a larger game, but if it's still small surely they can get it out within a year and a half of Hellblade 2, especially since a significant chunk of work was already done before Hellblade 2 released. 

As great as it would be for Double Fine to surprise us all with their new game, I'm doubting it's them. That "surprise location" is throwing me off. San Francisco, where Double Fine is based, isn't exactly what I would consider a surprising location lol

Of course would love to be wrong, but I just highly doubt one of the most famous cities in the world would be considered surprising.

I think surprise location just means a studio they aren't revealing now because it's as brand new announcement. The Xbox Wire article makes a point of noting where each of the 3 announced studios are located, Richardson Texas, Montpelier France, and Montreal Canada. The goal is to show how diverse Xbox is, offering games from a variety of locations and cultures. By surprise location they could mean the location itself will be surprising (somewhere in Asia of course being the most surprising thing possible for Xbox), but it could also just mean the game/studio/where the studio is located is a surprise because it is being saved for the actual direct.

I mean obviously I hope they have some 2nd party Asian game to announce, but I'm very skeptical of it, Phil dangled that carrot on a stick in front of my face for far too long with no payoff. Double Fine feels far more likely to me with them going back to multiple smaller projects and having 3 and a half years almost to develop a game since Psychonauts 2, in the past Double Fine could churn out smaller games in less than 2 years per team, so taking into account development being slower now, almost 3.5 years of development seem plenty for their smaller projects.