There's no reason why MachineGames shouldn't be ready to show SOMETHING that they've been working on. The last "release" was a DLC for the Quake Remaster in 2021. They haven't had a big release since 2019. That's been more than enough time to show either at least a CGI trailer for Indiana Jones or you would think also working on Wolfenstein 3 this whole time.
It's been over 2 years since id Software wrapped up development on Doom Eternal. So I'm not sure if they're ready to tease what they could be working on. So they're a wild card.
The only other studios that I can see could have a presence is Roundhouse Studios. Primarily been assisting on development with Redfall, but they've been rumored to be working on a new IP for a while, and of course, ZOS needs to show off what their new IP is too lol. It'll have been 5 years in development.