A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
First pattern tailor-made for Retina, with many more to come. All the old ones are upscaled, in case you want to re-download.
Source Atle Mo
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
These dots are already worn for you, so you don’t have to.
Source Matt McDaniel
Just like your old suit, all striped and smooth.
Source Alex Berkowitz
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
Your eyes can trip a bit from looking at this – use it wisely.
Source Michal Chovanec
The tile this fill pattern is based on can be had by using shift+alt+i on the rectangle.
Source Firkin
Vertical lines with a bumpy, yet crisp, feel to it.
Source Raasa
It’s an egg, in the form of a pattern. This really is 2012.
Source Paul Phönixweiß
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Groovy Concentric Background 2 No Black
Source GDJ
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
A seamless pattern formed from cross 4. To get the original tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Abstract Geometric Monochrome Pattern Prismatic No Background
Source GDJ
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
From a drawing in 'Heroes of North African Discovery', Nancy Meugens, 1894.
Source Firkin