Yes, new core races give a little flavor as does a new base class. However, in 3rd edition (or 3.75 as some call Pathfinder) races are much easier than classes. There are three good options to pick from for races to add.
Lesser Ogre / Lesser Giant
- Using rules that imply big size such as like Wizards' goliath race.
Lizardfolk
- PC type lizard character with LA +0 but not Dragon-themed
Pixie
- Nonflying tiny faerie (ok this is a bit of a stretch)
