A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Seamless Prismatic Pythagorean Line Art Pattern No Background. A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Colour version of the original pattern.
Source Firkin
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
Subtle scratches on a light gray background.
Source Andrey Ovcharov
This was formed by distorting an image of a background on Pixabay.
Source Firkin
A new take on the black linen pattern. Softer this time.
Source Atle Mo
Redrawn based on a drawing in 'По Сѣверо-Западу Россіи' Konstantin Sluchevsky, 1897.
Source Firkin
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
The starting point for this was a texture drawn with the 'Radial Colors' plug-in in Paint.net.
Source Firkin
A seamless pattern formed from background pattern 102
Source Firkin
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
Submitted as a black pattern, I made it light and a few steps more subtle.
Source Andy
A seamless background pattern of dark brown wood planks.
Source V. Hartikainen
Derived from a JPG that was uploaded to Pixabay by ractapopulous
Source Firkin
Thin lines, noise and texture creates this crisp dark denim pattern.
Source Marco Slooten
A comeback for you: the popular Escheresque, now in black.
Source Patten
Tile-able Dark Brown Wood Background. Feel free to use it as a background image in your designs or somewhere on the web. By the way, the color seems to be close to Coffee Brown.
Source V. Hartikainen
An abstract Background pattern of purple twisty patterns.
Source TikiGiki
Remixed from a drawing in 'The March of Loyalty', Letitia MacClintock, 1884.
Source Firkin
You were craving more leather, so I whipped this up by scanning a leather jacket.
Source Atle Mo
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin