The idea of a lion or large bear attacking a whole party is pretty silly, but a hungry one might attack a solitary PC, and could make a pretty good account of itself in the role.
Boars make a sensible opponent, but you wouldn't expect them to win.
The crocodile's improved grab doesn't work on medium-sized opponents, while the giant crocodile(also known as mature salt-water crocodile) is only going to take one party-member, but may do so while they are with the rest of the party...
Elephants are pretty docile and unless they are being controlled, or are being freed from captivity, there is little reason for a good-aligned party to be fighting one.
Warhorses are not opponents, they are a vehicle, and you are only meant to be fighting the ones with turrets...
A dozen apes might attack a party, Baboons too. A large pack of particularly hungry dogs, wolves, or hyenas, but probably only after they were fatigued...
A monitor lizard might take a shot if you were on its turf. An octopus might do some damage, but for some reason they forgot to include the wyvern poison on their bite attack...
A giant squid would have a go, but again would probably leave after it had a single victim. A pod of Orca would definitely attack a party, but most parties don't swim...
The real problem is that most animals don't have the intelligence score to pose a credible threat that a party would bother with, the most likely scenario is that the party is hunting down a specific animal that has taking a liking to people... But even then, the challenge will be to find the thing, rather than to actually fight it...