Polyhaven (https://polyhaven.com/)
daz freebies - changing from time to time (https://www.daz3d.com/free-3d-models)
Wilmap's Digital Creations (https://www.wilmapsdigitalcreations.co.uk/introduction.php)
SdeBStore freebies (https://www.sdebstore.com/collections/free-stuff)
3d shards (https://3dshards.com/product-tag/free/)
I hope to fill in more pages :)