Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
This one is super crisp at 2X. Lined paper with some dust and scratches.
Source HQvectors
I love cream! 50x50px and lovely in all the good ways.
Source Thomas Myrman
A dark metal plate with an embossed grid pattern and a bit of rust. Here's a dark metal plate texture for use as a tiled background on web pages.
Source V. Hartikainen
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Looks like an old rug or a computer chip.
Source Patutin Sergey
This one resembles a black concrete wall when is tiled. It should look great, at least with dark website themes.
Source V. Hartikainen
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
A seamless background pattern of dark brown wood planks.
Source V. Hartikainen
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
A bit like smudged paint or some sort of steel, here is scribble light.
Source Tegan Male
Prismatic Hexagonalist Pattern No Background
Source GDJ
Not even 1kb, but very stylish. Gray thin lines.
Source Struck Axiom
Greyscale version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso