None for a while. I love the sequels that Pixar has been making (even Cars 2), but I think after Toy Story 4, I would like to see a pluthra of original films, before jumping back into sequels. While I would love to see Mike and Sulley again, I don't want a sequel to Monsters Inc (because of it's perfect ending, unless it can be really great). I don't want a sequel to Ratatouille, Wall-E, Up, Inside Out and Coco. A sequel to A Bug's Life, Brave and The Good Dinosaur are all unlikely and I don't really want those either. Maybe the Finding Nemo series will get another entry, but I think out of all of them the one with the most potential is Incredibles 3. I'm not sure I want that either though. I don't know what I want, whatever Pixar gives me I'll take, honestly.
We are seeing Mike and Sulley again in that upcoming Monsters TV series set to air on their new streaming service next year, to what extent is unknown (seeing as Monsters U did not make enough money at the box office to justify a third film happening, a TV series is outright perfect for them and would be the best way to continue and end the franchise on a good note, if I'm not mistaken, outside of A Bug's Life and the Cars series, they are the least popular franchise Pixar has).
A sequel to Brave not happening? Mark Andrews would like to have a word with you, while he's not interested in one right now (due to Pixar's upcoming film releases are all originals so far), he is thinking about a 2nd film, so a Brave sequel isn't out of the realm of possibility, it's really up to Disney/Pixar if they want to explore Merida's world more or not, they have the final say.
The Finding series is definitely getting a third film, with Dory getting $1 billion, they are most likely to get a third film well before we get a third Incredibles (unless the latter happens first).
Owen Wilson clearly wants a 4th Cars and has talked about it and they want it to return to the spy/thriller genre from Cars 2 (hopefully no Mater as the lead).
Again Incredibles 3 is the most obvious one and is the most likely one to happen (again due to getting $1 billion), could very well be their last sequel they ever do on that series before sticking with originals for good (and it would be a good swan song for some of the cast members who are going to be well over 60 when they do start up on that film).