The ID is usually found in the URL when you view an avatar in your browser, or it can be copied from the VRChat menu in-game. It looks like a string of letters and numbers (e.g., avtr_12345678-90ab-cdef-1234-567890abcdef ).
A: No. All major websites have been shut down or patched by VRChat's API authentication requirements. vrchat avatar id downloader link
You can find this ID easily: