So at a bare minimum there are 2:>
There is whatever project Wiz has been working on since he left Stellaris to lead up a different project.
This project is likely whatever Chris King was designing from 2016-2018 as he left Paradox about the same time Wiz moved over.
It is hoped by many that said project is Victoria III, but it could be that Stellaris 2 is being built from the ground up by Wiz and whatever Chris was working on was outright canceled.
You also have whatever Harebrained Schemes has been working on since Battletech was completed.
This could be a sequel of sorts to Battletech (4th Succession war maybe), some sort of Shadowrun Title, or mabye Crimson Skies?
Total speculation on my part, but I would guess that Design of EU5 is already under way and Johan and the Barcelona team will be working on it in the near future once the final design is nailed down.