Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
Not so subtle. These tileable wood patterns are very useful.
Source Elemis
Tile available in Inkscape using shift-alt-i on the selected rectangle
Source Firkin
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Light gray grunge wall with a nice texture overlay.
Source Adam Anlauf
Here's an yet another background for websites, with a seamless texture of wood planks this time.
Source V. Hartikainen
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.
Source Firkin
Black & white version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
Prismatic Hexagonalism Pattern No Background
Source GDJ
Black brick wall pattern. Brick your site up!
Source Alex Parker
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Submitted by DomainsInfo – wtf, right? But hey, a free pattern.
Source DomainsInfo
One more in the line of patterns inspired by Japanese/Asian styles. Smooth.
Source Kim Ruddock
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
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
Alternative colour scheme for the original floral pattern.
Source Firkin
Zero CC tileable grass texture, photographed and made by me. CC0
Source Sojan Janso
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Brushed aluminum, in a bright gray version. Lovely 2X as well.
Source Andre Schouten
Formed by distorting a JPG from PublicDomainPictures
Source Firkin
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin