8 by 8 pixels, and just what the title says.
Source pixilated
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
Remixed from a drawing in 'Works. Popular edition', John Ruskin, 1886.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A version without colours blended together to give a different look.
Source Firkin
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
A repeating background with seamless texture of stone. There haven't been any stone-like backgrounds for a while, so I have decided to create one more. The rest can be found in the appropriate category.
Source V. Hartikainen
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
I’m starting to think I have a concrete wall fetish.
Source Atle Mo
Brushed aluminum, in a bright gray version. Lovely 2X as well.
Source Andre Schouten
One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Background formed from the original with an emboss effect.
Source Firkin
White circles connecting on a light gray background.
Source Mark Collins