A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
A bit like smudged paint or some sort of steel, here is scribble light.
Source Tegan Male
A seamless gray background texture suitable for use on websites. To me, it has the look of stone. Feel free to modify it to meet your needs (by making it a bit lighter or darker, for example).
Source V. Hartikainen
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
This is the remix of "Strawberry Pattern Background" uploaded by "GDJ". Thanks. I realigned strawberries so as to get seamless and changed the BG color.
Source Yamachem
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
A light gray wall or floor (you decide) of concrete.
Source Atle Mo
A seamlessly tile-able grunge background image.
Source V. Hartikainen
Continuing the geometric trend, here is one more.
Source Mike Warner
Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.
Source Atle Mo
We have some linen patterns here, but none that are stressed. Until now.
Source Jordan Pittman
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin
More Japanese-inspired patterns, Gold Scales this time.
Source Josh Green
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
Smooth Polaroid pattern with a light blue tint.
Source Daniel Beaton