From a drawing in 'A Rolling Stone. A tale of wrongs and revenge', John Hartley, 1878.
Source Firkin
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Might not be super subtle, but quite original in its form.
Source Alex Smith
Inspired by a 1930s wallpaper pattern I saw on TV.
Source Firkin
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
Super dark, crisp and detailed. And a Kill Bill reference.
Source Badhon Ebrahim
No idea what Nistri means, but it’s a crisp little pattern nonetheless.
Source Markus Reiter
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Feel free to download this "Dark Wood" background texture for your web site. The background tiles seamlessly!
Source V. Hartikainen
In the spirit of WWDC 2011, here is a dark iOS inspired linen pattern.
Source Atle Mo
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Sweet and subtle white plaster with hints of noise and grunge.
Source Phil Maurer
Same classic 45-degree pattern, dark version.
Source Luke McDonald
Prismatic Abstract Geometric Background 2
Source GDJ
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
Sort of like the Photoshop transparent background, but better!
Source Alex Parker
Super detailed 16×16 tile that forms a beautiful pattern of straws.
Source Pavel
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin