A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
Abstract Ellipses Background Grayscale
Source GDJ
Prismatic Snowflakes Pattern 3 No Background
Source GDJ
A new take on the black linen pattern. Softer this time.
Source Atle Mo
You could get a bit dizzy from this one, but it might come in handy.
Source Dertig Media
A seamless pattern formed from miutopia's cakes on a tablecloth.
Source Firkin
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
Tile-able Dark Brown Wood Background. Feel free to use it as a background image in your designs or somewhere on the web. By the way, the color seems to be close to Coffee Brown.
Source V. Hartikainen
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
Seamless Dark Grunge Texture. Here's a new grunge texture for use as a background.
Source V. Hartikainen
Detailed but still subtle and quite original. Lovely gray shades.
Source Kim Ruddock
Prismatic Curved Diamond Pattern 4 No Background
Source GDJ
This was formed by distorting an image of a background on Pixabay.
Source Firkin
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
This is the remix of "polka dot seamless pattern".The image depicts polka dot seamless pattern.
Source Yamachem
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 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Not the Rebel alliance, but a dark textured pattern.
Source Hendrik Lammers
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
A seamless pattern the starting point for which was a 'colour modulo' texture in Paint.net.
Source Firkin
A bit like smudged paint or some sort of steel, here is scribble light.
Source Tegan Male
Prismatic Polyskelion Pattern No Background
Source GDJ
Light gray pattern with an almost wall tile-like appearance.
Source Markus Tinner
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin