The following repeating website background is colored in a blue gray color and resembles a concrete wall or something similar to it.
Source V. Hartikainen
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
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Remixed from a JPG that was uploaded to Pixabay by susanlu4esm
Source Firkin
Alternative colour scheme for the original floral pattern.
Source Firkin
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A light gray fabric pattern with faded vertical stripes.
Source V. Hartikainen
This could be a hippy vintage wallpaper.
Source Tileable Patterns
Thin lines, noise and texture creates this crisp dark denim pattern.
Source Marco Slooten
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i
Source Firkin
Background formed from the iconic plastic construction bricks that gave me endless hours of fun when I was a lad.
Source Firkin
There are many carbon patterns, but this one is tiny.
Source Designova
A large pattern with funky shapes and form. An original. Sort of origami-ish.
Source Luuk van Baars
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
On a large canvas you can see it tiling, but used on smaller areas, it’s beautiful.
Source Paul Phönixweiß
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
The image is a design of blue glass.How about using it as background image?
Source Yamachem
Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
Colour version of the original pattern inspired by the front cover of 'Old and New Paris', Henry Edwards, 1894.
Source Firkin
A free tileable background colored in off-white (antique white) color.
Source V. Hartikainen
Inspired by a pattern found in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin