All shared sounds have a CC0 (public domain) license.
Please also consider posting your sound to the GSN Composer subreddit:
Here you can export the current sound to the GSN Composer.
The GSN Composer is a free online tool for visual programming and modular sound synthesis.
You can change the structure of the synthesizer, trigger notes with a step sequencer,
record the output and save it as a WAV file, and much more.