Dominique Huchet (aka tinga) has released two free Corona sound banks.
Birds & Noises
Birds presets use osc3 like a LFO, using the "Classic Wav" folder, so you can change the song by changing the wave, by this way playing on your keyboard you can create infinity of birds song, many other presets use osc3 as LFO.
www.youtube.com/watch?v=MH6nAPmrpsk
Wendy
An attempt to create some instrumental textures, presets using Just Intonation or Indian tunings are in C.