Wow!  This fella made loads and loads of his HDR's free, using CC0 licensing.  Which means you can basically use them for any purpose.

https://hdrihaven.com/

Do the right thing, and donate a bit to his Patreon page so he can keep churning out content that everyone can use.

HDRI Haven is creating free, high quality HDRIs for everyone | Patreon

Ron