An emulated “transparent” background pattern, like that of all kinds of computer graphics software.
Source AdamStanislav
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
Prismatic Abstract Geometric Background derived from an image on Pixabay.
Source GDJ
A very slick dark rubber grip pattern, sort of like the grip on a camera.
Source Sinisha
This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley
Tiny circle waves, almost like the ocean.
Source Sagive
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
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
A free green background pattern with a pattern of rhombuses on a seamless texture. Feel free to use it as a tiled background image on your web site.
Source V. Hartikainen
Inspired by this, I came up with this pattern. Madness!
Source Atle Mo
A free background pattern with abstract green tiles.
Source V. Hartikainen
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
A seamless background pattern with a texture of wood planks. This wood background pattern has vertically arranged planks. You may try to rotate it 90°, to see how it will look like when the wood planks are arranged horizontally.
Source V. Hartikainen
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
This texture looks like old leather. It should look great as a background on web pages.
Source V. Hartikainen
A free black metallic background pattern. Here's a new pattern I made that looks metallic.
Source V. Hartikainen
Feel free to download this "Dark Wood" background texture for your web site. The background tiles seamlessly!
Source V. Hartikainen