The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Brushed aluminum, in a bright gray version. Lovely 2X as well.
Source Andre Schouten
Actually, there's no clouds in it, but I think it looks quite nice.
Source V. Hartikainen
Pattern produced in Paint.net using the Vibrato plug-in.
Source Firkin
Background Wall, Art Abstract, Watercolor Vintage style CC0 texture.
Source Ractapopulous
Colour version of the original pattern inspired by the front cover of 'Old and New Paris', Henry Edwards, 1894.
Source Firkin
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
Here's a bluish gray striped background pattern for use on web sites.
Source V. Hartikainen
Just a nice looking textured pattern with faded blue stripes. Well, that's it for today... one background a day, as usual.
Source V. Hartikainen
A light background pattern with diagonal stripes. Here's a simple light striped background for you.
Source V. Hartikainen
Prismatic Abstract Geometric Background 4 No Black
Source GDJ
Prismatic Abstract Line Art Pattern Background 2
Source GDJ
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Here's a camo print with more tan and less green, such as might be used in a desert scenario. This is tileable, so it can be used as a wallpaper or background.
Source Eady
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
A criss-cross pattern similar to one I saw mown into a sports field.
Source Firkin
The perfect pattern for all your blogs about type, or type-related matters.
Source Atle Mo
A textured blue background pattern with vertical stripes.
Source V. Hartikainen
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
In the spirit of WWDC 2011, here is a dark iOS inspired linen pattern.
Source Atle Mo
A seamless pattern formed from a sports car on clker.com. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin