From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
Prismatic Curved Diamond Pattern 2 No Background
Source GDJ
This one resembles a black concrete wall when is tiled. It should look great, at least with dark website themes.
Source V. Hartikainen
It’s an egg, in the form of a pattern. This really is 2012.
Source Paul Phönixweiß
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
Prismatic Snowflakes Pattern No Background
Source GDJ
Prismatic Polyskelion Pattern No Background
Source GDJ
Simple wide squares with a small indent. Fits all.
Source Petr Šulc.
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
One more in the line of patterns inspired by Japanese/Asian styles. Smooth.
Source Kim Ruddock
Otis Ray Redding was an American soul singer-songwriter, record producer, arranger, and talent scout. So you know.
Source Thomas Myrman
The original enhanced with some gradients.
Source Firkin
Remixed from a drawing that was uploaded to Pixabay by ractapopulous
Source Firkin
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
The texture of this background image has some similarities with leather, and it's colored in a dark brown color. So, if you are looking for a dark brown background image for your website, this may be an option for you.
Source V. Hartikainen
Super detailed 16×16 tile that forms a beautiful pattern of straws.
Source Pavel
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
The classic notebook paper with horizontal stripes.
Source Are Sundnes
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Alternative colour scheme. Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin