BittBox
I’ve mentioned this first set before, but everybody loves BittBox, right? Available in AI, EPS, SVG, and vector PSD. License and Usage Info.

Here’s another set. Available in EPS and SVG formats. License and Usage Info.

Snap2Objects
Snap2Objects offers this nice set of foliage silhouettes as an EPS file.

LAFKON (Vecteezy)
Here’s a set that’s a little different. AI file. Released under ” Creative Commons Sampling License Plus+.”

The Hybrid Agency (Neno Design)
Some more cool silhouettes. EPS file. Personal use only.

Takashi Irie
Some cool foliage ornaments. Available in EPS and AI formats.

Pixlpusher
A nice EPS file (very cool background, too).