A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman
Square design drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Lovely pattern with some good-looking non-random noise lines.
Source Zucx
If you don’t like cream and pixels, you’re in the wrong place.
Source Mizanur Rahman
A floral background formed from numerous clones of flower 117.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
An alternative colour scheme to the original seamless pattern.
Source Firkin
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
Actually, there's no clouds in it, but I think it looks quite nice.
Source V. Hartikainen
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
Produced using the clouds, flames and glass blocks plug-ins in Paint.net and the resulting .PNG vectorised with Vector Magic.
Source Firkin
This is a seamless pattern which is derived from a flower petal image.
Source Yamachem
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Groovy Concentric Background 3 No Black
Source GDJ
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin