Sonnis is giwing away some of their sound effects. State from the website:
"In celebration of GDC 2018 we are giving away 30GB+ of high-quality sound effects from our catalog. Everything is royalty-free and commercially usable. No attribution is required and you can use them on an unlimited number of projects for the rest of your lifetime.
All of the files we send out are just a small sample of our suppliers complete collection. We usually pick a couple of sounds from each library added to Sonniss over the year. None of the files we are giving away have been modified in any way, they are exactly the same files we sell. If you would like more options and design choices to work with, please consider purchasing the corresponding collection."
You can download everithing as zip files or in one big torrent file.