Little cockroach people. They take the place of gnomes/halflings. They're small, have four arms, vestigial wings (the adults can fly for very short distances and then only awkwardly... it's a rare member who is good enough at flying to actually gain altitude) and are very skilled with their hands. They'll look more comical than buglike... didn't Swordbearer have a race like this? I could even make them clumsy overall, by separating out Agility and Dexterity, but I'm not sure it's worth the trouble. In attitude, they're mostly inoffensive homebodies... they may look a bit like bugs, but they act like small humans in many ways.
Salamanders and Undines might make decent PC races. Salamanders are fire elementals bound up inside metal armor. They can eat anything that burns well and can endure any amount of heat, but they're somewhat vulnerable to cold and if their armor is damaged they tend to hemorhage flame until it gets fixed. The ones that are interested in non-fire realms are regarded as perverts and weirdos by their own kin. They might be engaged in a long civil war at home with another kind of fire-creature.
Undines are shape-shifting water people. They're not very strong or tough, but they don't need to breathe and can mold their bodies into almost any form (only their shape changes, not their mass or nature; think Plasticman). They can also recover from injuries very rapidly. They only need water to live and can generally filter it out of other liquids if they need to. They often suffer from a kind of wanderlust; they yearn for the "perfect place" to settle down and go looking for it. They often have "false alarms", where they think they've found the perfect spot, but grow weary of it and move on. Ones that have already found their perfect spot just stay there, living quite happily and the envy of other Undines... they defend these homes fanatically.
Free willed golems: very rare, but possible. You don't need to eat, drink, breathe or sleep. You "see" by sensing mass, and can recognize the presence of any physical object. You have to be incredibly old, because otherwise you'd be mute and nearly mindless, so you've seen a lot. But on the other hand, you have a special vulnerable spot (your soulstone) and lots of people consider that worth stealing. Your Intuition rating tends to tank, though... golems are not sensitive, intuitive folks.
Centaurs: these huge, brutish Clydesdales with orc/neanderthal-like upper bodies. Strong, tough and fast, if oversized. Not known for being too bright and they heal relatively slowly. Their culture is relatively barbaric in the "Conan" sense... they're independent and superstitious, but fiercely honorable and brave. Most of the ones that end up in Menagerie are outcasts, often because they challenged a tribal leader for his position and lost. Their eyesight is bad, making them hopeless archers.
Lendehar: these tall, spindly humanoids are natural born scholars... very smart, very intuitive. They were created by a beneficient god of knowledge long, long ago, before he went mad and became the totally insane isolationist demon-god. They have survived by making themselves useful to other races and tend to be humble and pacifistic.
Earth elementals make lousy PCs because they travel through rock and hate coming out into the open where the rest of the PCs are. Similarly, air elementals haven't been seen in Menagerie since time immemorial; even the other elementals aren't really sure what they're like anymore... Menagerie is the only direct contact that they have. In fact, the various breeds of elemental probably get offended at being lumped in together, much like many humans would if someone regarded them as the same as all other vertebrates.