Snap! It’s a pattern, and it’s not grayscale! Of course you can always change the color in Photoshop.
Source Atle Mo
The Grid. A digital frontier. I tried to picture clusters of information as they traveled through the computer.
Source Haris Šumić
A seamless pattern the starting point for which was a 'light rays' rendering in Paint.net.
Source Firkin
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
Zero CC tileable cork floor, photographed and made by me. CC0
Source Sojan Janso
On a large canvas you can see it tiling, but used on smaller areas, it’s beautiful.
Source Paul Phönixweiß
Background pattern originally a PNG drawn in Paint.net
Source Firkin
Prismatic Groovy Concentric Background 3
Source GDJ
Turn your site into a dragon with this great scale pattern.
Source Alex Parker
White fabric looking texture with some nice random wave features.
Source Hendrik Lammers
A light gray background pattern with seamless fabric-like texture and almost unnoticeable stripes.
Source V. Hartikainen
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
This one is quite simple in design, it consists of vertical stripes layered on top of a seamless texture.
Source V. Hartikainen
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
A light background pattern with diagonal stripes. Here's a simple light striped background for you.
Source V. Hartikainen
An interesting dark spotted pattern at an angle.
Source Hendrik Lammers
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
You may use it as is, or modify it as you like.
Source V. Hartikainen
From a drawing in 'Az Osztrák-Magyar Monarchia irásban és képben', 1885.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Did anyone say The Hoff? This pattern is in no way related to Baywatch.
Source Josh Green
Prismatic Groovy Concentric Background 5 No Black
Source GDJ