From a drawing in 'Handbook of the excursions proposed to be made by the Lincoln Diocesan Architectural Society, on the 27th and 28th of May, 1857', Edward Trollope, 1857.
Source Firkin
This background has abstract texture with some similarities to wood.
Source V. Hartikainen
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
A bit like smudged paint or some sort of steel, here is scribble light.
Source Tegan Male
This is the remix of "polka dot seamless pattern".The image depicts polka dot seamless pattern.
Source Yamachem
Formed by distorting a JPG from PublicDomainPictures
Source Firkin
This background pattern has futuristic look. So, maybe it could be used on websites or blogs dedicated to video games?!
Source V. Hartikainen
From a drawing in 'Friend or Fortune? The story of a strange year', Robert Overton, 1897.
Source Firkin
Simple wide squares with a small indent. Fits all.
Source Petr Šulc.
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
Beautiful dark noise pattern with some dust and grunge.
Source Vincent Klaiber
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
A seamless background pattern with a texture of wood planks. This wood background pattern has vertically arranged planks. You may try to rotate it 90°, to see how it will look like when the wood planks are arranged horizontally.
Source V. Hartikainen
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin