Light and tiny, just the way you like it.
Source Rohit Arun Rao
A seamless background colored in pale orange. It has a paper like texture with diagonal grid pattern.
Source V. Hartikainen
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
Prismatic Abstract Background Design
Source GDJ
Abstract Tiled Background Extended 11
Source GDJ
Seamless Prismatic Geometric Pattern With Background
Source GDJ
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
Like the name suggests, this background image consists of a pattern of dark bricks. It may be an option for you, if you are looking for something that looks like a brick wall for use as a background on web pages. It's not a masterpiece, but looks pretty nice when is tiled.
Source V. Hartikainen
From a drawing in 'Cassell's Library of English Literature', Henry Morley, 1883.
Source Firkin
As simple and subtle as it gets. But sometimes that’s just what you want.
Source Designova
Tweed is back in style – you heard it here first. Also, the @2X version here is great!
Source Simon Leo
Colorful Floral Background No Black
Source GDJ
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Zero CC tileable cork floor, photographed and made by me. CC0
Source Sojan Janso
A repeating background with seamless texture of stone. There haven't been any stone-like backgrounds for a while, so I have decided to create one more. The rest can be found in the appropriate category.
Source V. Hartikainen
From a drawing in 'Hundert Jahre in Wort und Bild', S. Stefan, 1899.
Source Firkin
Prismatic Rounded Squares Grid 3 No Background
Source GDJ
Prismatic Geometric Tessellation Pattern 3 No Background
Source GDJ
A seamlessly tile-able grunge background image.
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso