8 by 8 pixels, and just what the title says.
Source pixilated
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
Sort of like the Photoshop transparent background, but better!
Source Alex Parker
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Remixed from a design on Pixabay. To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
A bit like some carbon, or knitted netting if you will.
Source Anna Litvinuk
Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
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
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
A free seamless background texture that looks like a brown stone wall.
Source V. Hartikainen
A seamless striped fabric-like texture colored in a dark reddish brown color.
Source V. Hartikainen
Feel free to use this seamless background texture as a background on a web site. It's colored in a light pink color and is seamlessly tile-able.
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Prismatic Hexagonalist Pattern No Background
Source GDJ
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Abstract Arbitrary Geometric Background derived from an image on Pixabay.
Source GDJ
Derived from a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
There are quite a few grid patterns, but this one is a super tiny grid with some dust for good measure.
Source Dominik Kiss