Ok, so far the biggest problem is Dil and Ichy. In fact, they seem to be the only threat to the Gang of Five and Ali there.
I mean, in the first film, we had that evil lizard thingy, nasty Domeheads and the evil Sharptooth out there in the Mysterious Beyond.
In film V, there was this Sharp Beak thingy that almost fed Ducky to her babies, not to mention Chomper's hungry parents, and the evil Plated Sharptooth out there on the Mysterious Island.
Heck, the TV Series probably had the most dangers, many of them in "The Lonely Journey" where even being a Sharptooth doesn't make you safe!