The only film that really needs a continuation is
The Incredibles.And I'm of the opinion Pixar needs to shelve Toy Story now and focus on something else.
You can't just keep milking the same franchise over and over.
What if they were to keep trading the toys to new owners every 2-3 years just so the franchise has a reason to keep going?
That's poor storytelling technique.
Brave may have a sequel, but that's unconfirmed.
The only thing I've heard is that the sequel may explore Merida's relationship with the one son of the chiefs she actually had a fondness for:
http://pixar.wikia.com/Young_MacGuffinHer reactions to him are markedly different to the others, she's more pleasant and doesn't insult him like the other sons.
I'm assuming this is because he was more friendly then the other sons, he wasn't obnoxious or aggressive like they were.
You could almost see he's a bit shy, because when he breaks the log, he's got an expression that he doesn't really want to be the center of attention.
As for non-Pixar films (pure Disney), I'm uncertain if any others need sequels.
I can't really think of anything that would lend itself to a continuing series.
I'll have to give it some more thought and see if I can think of anything.
I wouldn't say no to more Frozen stories though, if they can come up with compelling ones.