Constructing a monster hunter campaign need some cool monsters!

[Glumph]

It's my first time dming and I thought I'd try a pretty simple monster hunting campaign. The rules so far are as follow:
1)Only core books and faerun campaign setting books allowed no psionics
2)Characters are starting at level 10
3)They're all getting 28 point buys but I'm steering the party away from tier 1 and 2 classes LA buy off is allowed as is 2 flaws ( i want them to optimize so i have more freedom for more interesting encounter)

The party will in essence be tracking down and slaying beasts of legend. I'm looking for some interesting monsters magical or not that have different and challeneging mechanics other than just hack and slash any help would be much appreciated

[Ezekiul]

Well a lot of legendary creatures are hack and slash, because most gain that status through strength and power. Dragon and Chimeras can fly, nymphs and medusas have various visual abilities, maybe some kind of buffed up blink dog with its free action teleports. Other "legendary" creatures that come to mind but might be a bit more hack and slash would be hydras, legendary animals (MM4 iirc), tarrasque, and kraken. If your not afraid of giving class levels, maybe some kind of illusionist beholders or mindflayers could be implemented.

[Uhtred]

The vicious Dogsnake! Or the legendary Displacer Moose!
http://shawntionary.com/chainmailbikini/?p=49

[Downysole]

Go watch some old Ray Harryhausen flicks and pick a genre.

Take them through Clash of the Titans, Sinbad, Jason and the Argonauts. Each could be a kind of adventure on its own. Most of these creatures have been statted up in the MM, and if they haven't, I'm sure you can ask here for a quick reference to a cyclops.

[Psyren]

Mix things up with exotic creature types. Oozes, Plants and Giants don't get enough exposure imo.