Here I have tried to create something that would look like maple wood. Not sure how well it's turned out, but at least it looks like wood.
Source V. Hartikainen
The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Formed by heavily distorting part of a an image of a fish uploaded to Pixabay by GLady
Source Firkin
Drawn in Paint.net and vectorised in Vector Magic
Source Firkin
I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
This is a remix of "blue wave-seigaiha".I hope this subtle color version of Seigaiha would be suitable for background .
Source Yamachem
This light background pattern has a texture of "frozen" surface with diagonal stripes. Here's an yet another addition to the collection of free website backgrounds.
Source V. Hartikainen
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
With a name this awesome, how can I go wrong?
Source Nikolay Boltachev
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
A large pattern with funky shapes and form. An original. Sort of origami-ish.
Source Luuk van Baars
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Inspired by a drawing in 'Poems', James Smith, 1881.
Source Firkin
Prismatic Polyskelion 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
Background formed from the original with an emboss effect.
Source Firkin
Not so subtle. These tileable wood patterns are very useful.
Source Elemis
Remixed from a drawing in 'Some account of the Worshipful Company of Ironmongers', John Nicholl, 1866.
Source Firkin
A bit simplified version. Although it could be edited out to be simpler. Anyway, this time the tiling is converted to a pattern fill -which is using clipping for the tile's edges.
Source Lazur URH