CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
An interesting dark spotted pattern at an angle.
Source Hendrik Lammers
Fix and cc0 to get the tile this is based on.
Source SliverKnight
I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
A bit strange this one, but nice at the same time.
Source Diogo Silva
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
The image depicts a seamless pattern which was made using stripe-like things including borders.I used OCAL cliparts called "Blue Greek Key With Lines Border" uploaded by "GR8DAN" and "daisy border" uploaded by "johnny_automatic".Thanks.
Source Yamachem
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
From a drawing in 'Uit de geschiedenis der Heilige Stede te Amsterdam', Yohannes Sterck, 1898.
Source Firkin
The following orange background pattern resembles a honeycomb.
Source V. Hartikainen
A new take on the black linen pattern. Softer this time.
Source Atle Mo
This is the remix of "plant pattern 02".I changed the object color to white and the BG to purple.The image a seamless pattern derived from a weed which I can't identify.The original weed image is from here:jp.pinterest.com/pin/500744052301423641/
Source Yamachem
f you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
A very dark asfalt pattern based off of a photo taken with my iPhone.
Source Atle Mo
This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
It looks like a polished stone surface to me. Download it for free, as always.
Source V. Hartikainen
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
This light blue background pattern is quite pleasing to the eye, it consists of a tiny rough grid pattern, which is seamless by design. That's it, if you like the color, you can use this seamless pattern in a web design without making any further modifications to it.
Source V. Hartikainen