A dark gray, sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
An abstract texture of water. It's not perfect, but will do. You may download if you like it.
Source V. Hartikainen
Dark wooden pattern, given the subtle treatment. based on texture from Cloaks.
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
A seamless texture of black leather. I think it will look best when used in headers, footers or sidebars.
Source V. Hartikainen