Apparently not all of those are technically Blue Sky, though certainly they all come from Fox. Not sure what the differentiator is.
Anastasia was made by Don Bluth’s studio, and The Simpsons Movie is from Gracie Films.
Don Bluth was a director and producer, but Fox Animation is the production studio for Anastasia..
The Simpsons Movie
I was wrong about all those movies being Blue Sky. But, they all are definitely Fox Animation. Ownership can be... tricky.
E.g., while Disney Animation Studios and Pixar make their own movies with their own in-house studios, just about every live action movie from Walt Disney Studios is made by "a production company", very often, the director's own company made for legal and financial reasons.
Often, these companies are hired by Fox or Disney to make the movie for them to own and distribute. Which makes them a Fox or Disney property, even though their own studio didn't produce them.
Sometimes a smaller company creates a film and looks for a big studio to buy it and distribute it as if it were made by the big studio.
In Blue Sky's case, they were once an independent company and then Fox bought a majority stake in it and wound up owning what they had produced and tasked them with making more content to be distributed as a Fox/Blue Sky endeavor. What makes 'ownership' even crazier is that Fox Animation was the parent for Blue Sky. That would be like Pixar being a subsidiary of Disney Animation.
And once Blue Sky came on board, Fox Animation stopped making animated feature films (except for the collaboration with Gracie Studios for The Simpsons Movie), letting Blue Sky do that for them. So technically, every Blue Sky film is also a Fox Animation Film.
Fox Animation made just two theatrically release animated features: Anastasia and Titan A.E. The rest of Fox's feature animation films were made by Blue Sky, or, sometimes in conjunction with other studios, like Gracie. These are the only three on my list which Blue Sky Studio did not have a hand in, but were made by Fox Animation. But they were definitely owned by Fox and now, Disney.
And yes, sometimes the big studio is just a distributor and not only didn't create the movie, but has no ownership rights, but that's not the case here.