In order to make Renoise textures, we need to use seamless patterns tiling textures. In the past, I used to find easily those kind of graphical resources on a website called GRSites. This site has shutdowned a few years ago. By chance the free textures are available on the Internet Archive Wayback Machine. Here is the URL where you can still download a ZIP containing all the free textures.
Now it’s cool, but the pictures are old, often small, sometimes in bad quality. Thanks to @Jalex who requested a skulls & bones texture, I searched the web and realized that it is flooded with not-free graphical resources. So my question is: do you know some good websites to download free (let’s say royalty-free) textures, without having to create an account or to pay for a monthly subscription?