Some sites with useful free assets. The assets are completely free, i.e. have a CC0 zero license which means you can do whatever you want with them even commercially. There is even no need for attribution but of course giving credit is still the way to go (in my opinion).
Quite a few of these sites have a Patreon site, so you might consider becoming a patron. I have included a link where appropriate.
Note that the model sites listed here might be Blender specific, the texture and HDRI sites are definitely not.
https://www.3dassets.one/ This an aggregator site with a very useful search engine. The sites it provides links to however are always free but not always 100% CC0
https://texturebox.com/ Although the textures are free, it is unclear if those textures are CC0 https://www.patreon.com/texturebox
https://www.pbrhorde.com/ Although the textures are free, it is unclear if those textures are CC0 https://www.patreon.com/pbrhorde