8 by 8 pixels, and just what the title says.
Source pixilated
Seamless Green Tile Background
Source V. Hartikainen
It has waves, so make sure you don’t get sea sickness.
Source CoolPatterns
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.
Source Atle Mo
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
This light yellow background pattern consists of an irregular pattern of spots. Here's a light background pattern with yellowish tint.
Source V. Hartikainen
A simple but elegant classic. Every collection needs one of these.
Source Christopher Burton
No idea what Nistri means, but it’s a crisp little pattern nonetheless.
Source Markus Reiter
This white background pattern has a seamless grunge style texture. Here's a white grunge style background pattern. Use it as a tiled background image on web sites or for other purposes.
Source V. Hartikainen
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
Sort of reminds me of those old house wallpapers.
Source Tish
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
This was submitted in a beige color, hence the name. Now it’s a gray paper pattern.
Source Konstantin Ivanov
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Everyone loves a diamond, right? Make your site sparkle.
Source AJ Troxell
I asked Gjermund if he could make a pattern for us – result!
Source Gjermund Gustavsen
This seamless pattern consists of a blue grid on a yellow background.
Source V. Hartikainen
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen