A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
A light gray background pattern with seamless fabric-like texture and almost unnoticeable stripes.
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A pattern drawn in Paint.net and vectorized in Inkscape.
Source Firkin
From a drawing in 'Hyde Park from Domesday-Book to date', John Ashton, 1896.
Source Firkin
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
More tactile goodness. This time in the form of some rough cloth.
Source Bartosz Kaszubowski
Here's a tile-able wood background image for use in web design.
Source V. Hartikainen
Spice up your next school project with this icon background.
Source Swetha
Prismatic Curved Diamond Pattern 8 No Background
Source GDJ
From a drawing in 'Prose and Verse ', William Linton, 1836.
Source Firkin
Light gray version of the Binding pattern that looks a bit like fabric.
Source Newbury
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
A free seamless background with pink spots.
Source V. Hartikainen
A rusty grunge background for websites. Feel free to use it in your site's theme.
Source V. Hartikainen
This one is so simple, yet so good. And you know it. Has to be in the collection.
Source Gluszczenko
Zero CC tileable hard cover cells book texture, 4k, scanned and made by me. CC0
Source Sojan Janso
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Awesome name, great pattern. Who does not love space?
Source Nick Batchelor
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers