Grover (one of meow's favourites)
I saw "nature names" and straight away thought of Grover. It's the new River, get in before the popularity hits!

Zenith (love this!!)
Leaf
River
Banjo
Wren
Fox

There are a few good ones in Winter's Nicole Ritchie middle names thread too.
Give me your best Nicole Ritchie inspired middle names!! (Midnight / Winter)

ETA: I LOVE Griffin too!