Actually remixed from a pattern on Pixabay. But then noticed a very similar one on Openclipart.org uploaded by btj51q2.
Source Firkin
The image depicts a seamless pattern of a Japanese family crest called "chidori" in Japanese .A chidori in Japanese means a plover in English.
Source Yamachem
Sharp diamond pattern. A small 24x18px tile.
Source Tom Neal
It’s a hole, in a pattern. On your website. Dig it!
Source Josh Green
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prismatic Abstract Background Design No Black
Source GDJ
Little x’es, noise and all the stuff you like. Dark like a Monday, with a hint of blue.
Source Tom McArdle
Remixed from a drawing in 'A Girl in Ten Thousand', Elizabeth Meade, 1896.
Source Firkin
Here's a brown background pattern with subtle stripes. I hope you'll like the color. If not, feel free to change it using an image editor, if you know how of course. Personally, I'm using GIMP to create these backgrounds.
Source V. Hartikainen
An abstract texture of water. It's not perfect, but will do. You may download if you like it.
Source V. Hartikainen
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A tile-able background for websites with paper-like texture and a grid pattern layered on top of it.
Source V. Hartikainen
Brushed aluminum, in a bright gray version. Lovely 2X as well.
Source Andre Schouten
Geometric triangles seem to be quite hot these days.
Source Pixeden
Geometric lines are always hot, and this pattern is no exception.
Source Listvetra
Medium gray fabric pattern with 45-degree lines going across.
Source Atle Mo
A free seamless background texture that looks like a brown stone wall.
Source V. Hartikainen