If your party needs flying mounts, Dire Hawks/Eagles (Races of Stone) or Dire Bats (Or Desmodu bats from MMII) are all ~3-4 HD and could prove very useful.

If you want to dig your own mountain fortress, charm several dire badgers.

You could just spend 20g to do the same thing, but charm a dozen cows and then use the "auroch" rules to kill enemies via stampede!

Charm a variety of rats, mice, ferrets, and whatnot, then re-enact the Battle of Redwall or the Secret of Nimh :P