What is the name of the ambience sound from first levels of portal 2 (overgrown theme)? The one with sounds of crickets and other nature sounds.

That are some soundscape scripts: Klick

(If you mean that)

Search "insect" in the sound browser

Use the soundscapes, but if you want the raw sounds filter "ambient\nature\", make sure you select "raw files" since they don't have a soundscript entry. If you use the soundscape it'll automatically play most of those sounds for you at random times. You can also search for the "BirdBirdBird." soundscapes used for the Old Aperture Crow.

Just found out about soundscapes. Thanks so much!