I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
A background pattern with a look of rough fabric.
Source V. Hartikainen
More tactile goodness. This time in the form of some rough cloth.
Source Bartosz Kaszubowski
Three shades of gray makes this pattern look like a small carbon fiber surface. Great readability even for small fonts.
Source Atle Mo
Nothing like a clean set of bed sheets, huh?
Source Badhon Ebrahim
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
Abstract Arbitrary Geometric Background derived from an image on Pixabay.
Source GDJ
First pattern tailor-made for Retina, with many more to come. All the old ones are upscaled, in case you want to re-download.
Source Atle Mo
A nice and simple white rotated tile pattern.
Source Another One
An abstract texture of water. It's not perfect, but will do. You may download if you like it.
Source V. Hartikainen
From a drawing in 'Jardyne's Wife', Charles Wills, 1891.
Source Firkin
Seamless Light Background Texture.
Source V. Hartikainen
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
I’m not going to lie – if you submit something with the words Norwegian and Rose in it, it’s likely I’ll publish it.
Source Fredrik Scheide
Prismatic Curved Diamond Pattern 8 No Background
Source GDJ
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
If you need a green background for your blog/website, try this one. Remember that Green Striped Background is seamlessly tileable.
Source V. Hartikainen
Small gradient crosses inside 45-degree boxes, or bigger crosses if you will.
Source Wassim
Light gray pattern with an almost wall tile-like appearance.
Source Markus Tinner
Zero CC tileable pine bark texture, photographed and made by me. CC0
Source Sojan Janso
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers