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
Prismatic Groovy Concentric Background 3 No Black
Source GDJ
A seamless stone-like background for blogs or any other type of websites.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
This is lovely, just the right amount of subtle noise, lines and textures.
Source Richard Tabor
White fabric looking texture with some nice random wave features.
Source Hendrik Lammers
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
A new one called white wall, not by me this time.
Source Yuji Honzawa
Prismatic Polyskelion Pattern No Background
Source GDJ
To get the tile this is made up from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamlessly repeating background pattern of wood. The image is procedurally generated, and, I think, it's turned out quite well.
Source V. Hartikainen
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
Number 1 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
A background formed from an image of an old tile on the New York Metropolitan Museum of Art website. To get the base tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
Small gradient crosses inside 45-degree boxes, or bigger crosses if you will.
Source Wassim
Run a restaurant blog? Here you go. Done.
Source Andrijana Jarnjak
An alternative colour scheme for the original background.
Source Firkin