A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
A light background pattern with diagonal stripes. Here's a simple light striped background for you.
Source V. Hartikainen
Number 1 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Prismatic Curved Diamond Pattern 8 No Background
Source GDJ
Same classic 45-degree pattern, dark version.
Source Luke McDonald
One can never have too few rice paper patterns, so here is one more.
Source Atle Mo
From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.
Source Firkin
You know I love paper patterns. Here is one from Stephen. Say thank you!
Source Stephen Gilbert
Inspired by this, I came up with this pattern. Madness!
Source Atle Mo
Prismatic Groovy Concentric Background 5 No Black
Source GDJ
Smooth Polaroid pattern with a light blue tint.
Source Daniel Beaton
A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.
Source Atle Mo
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
This one is quite simple in design, it consists of vertical stripes layered on top of a seamless texture.
Source V. Hartikainen
Sharp pixel pattern, just like the good old days.
Source Paridhi
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
The image is a seamless pattern of a fishnet.
Source Yamachem
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
In the spirit of WWDC 2011, here is a dark iOS inspired linen pattern.
Source Atle Mo
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
Not so subtle. These tileable wood patterns are very useful.
Source Elemis
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857
Source Firkin
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin