A light brushed aluminum pattern for your pleasure.
Source Tim Ward
A seamless gray background texture suitable for use on websites. To me, it has the look of stone. Feel free to modify it to meet your needs (by making it a bit lighter or darker, for example).
Source V. Hartikainen
Prepared mostly as a raster in Paint.net and vectorised.
Source Firkin
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Seamless Olive Green Web Background Image
Source V. Hartikainen
Prismatic Polka Dots 3 No Background
Source GDJ
Just what the name says, paper fibers. Always good to have.
Source Heliodor jalba
Super dark, crisp and detailed. And a Kill Bill reference.
Source Badhon Ebrahim
One more in the line of patterns inspired by Japanese/Asian styles. Smooth.
Source Kim Ruddock
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
One more updated pattern. Not really carbon fiber, but it’s the most popular pattern, so I’ll give you an extra choice.
Source Atle Mo
Same as gray sand but lighter. A sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
A cute x, if you need that sort of thing.
Source Juan Scrocchi
Produced using the clouds, flames and glass blocks plug-ins in Paint.net and the resulting .PNG vectorised with Vector Magic.
Source Firkin
Everyone loves a diamond, right? Make your site sparkle.
Source AJ Troxell
Here's a new background image for websites with a seamless pink texture. It should look beautiful with website themes where light pink background is needed. The background is seamless, therefore it should be used as a tiled background.
Source V. Hartikainen
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
Abstract Ellipses Background Grayscale
Source GDJ
A simple example on using clones. You can generate a nice base for a pattern fill quickly with it.
Source Lazur URH