Here's a tile-able wood background image for use in web design.
Source V. Hartikainen
Seamless tile drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Prismatic Chevrons Pattern 5 With Background
Source GDJ
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Element of beach pattern with background.
Source Rones
Prismatic Abstract Background Design
Source GDJ
A black tile-able background with paper-like texture.
Source V. Hartikainen
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
The original enhanced with some gradients.
Source Firkin
Wild Oliva or Oliva Wilde? Darker than the others, sort of a medium dark pattern.
Source Badhon Ebrahim
Seamless Olive Green Web Background Image
Source V. Hartikainen
Just like your old suit, all striped and smooth.
Source Alex Berkowitz
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
A colourful background drawn originally in paint.net and vectorised in Vector Magic.
Source Firkin
A brown metallic grid pattern layered on top of a dark fabric texture. It should look great when using as a tiled background on web pages, especially blogs.
Source V. Hartikainen
Subtle scratches on a light gray background.
Source Andrey Ovcharov
Prismatic Isometric Cube Wireframe Pattern No Background
Source GDJ
A background formed from an image of an old tile on the New York Metropolitan Museum of Art website. To get the base tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A pattern formed from repeated instances of corner decoration 8. To get the basic tile select the rectangle in Inkscape and use shift+alt+i
Source Firkin