Here's a dark background pattern that contains a steel grid pattern as a texture. Use it as a website background or for other purposes. It's free!
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Number 4 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Prismatic Curved Diamond Pattern 6 No Background
Source GDJ
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i
Source Firkin
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
Similar to original, but without gaps in between the arrows. This seamless pattern was created from a rectangular tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Zero CC tileable hard cover red book, scanned and made by me. CC0
Source Sojan Janso
Seamless Olive Green Web Background Image
Source V. Hartikainen
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamlessly tileable pink background texture.
Source V. Hartikainen
A dark pattern made out of 3×3 circles and a 1px shadow. This works well as a carbon texture or background.
Source Atle Mo
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
From a drawing in 'Hubert Montreuil, or the Huguenot and the Dragoon', Francisca Ouvry, 1873.
Source Firkin
A car pattern?! Can it be subtle? I say yes!
Source Radosław Rzepecki
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba