I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
Nicely crafted paper pattern, although a bit on the large side (500x593px).
Source Blaq Annabiosis
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
Prismatic Groovy Concentric Background 5 No Black
Source GDJ
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
A repeating background with seamless texture of stone. There haven't been any stone-like backgrounds for a while, so I have decided to create one more. The rest can be found in the appropriate category.
Source V. Hartikainen
A seamless background of warped stripes on paper.
Source V. Hartikainen
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
From a drawing in 'Worsborough; its historical associations and rural attractions', Joseph Wilkinson, 1879.
Source Firkin
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
This seamless light brown background texture resembles a wallpaper with vertical stripes. One way to use it is as a tiled background on web sites.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868
Source Firkin
You know, tiny and sharp. I’m sure you’ll find a use for it.
Source Atle Mo
To get the tile this is made up from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Alternative colour scheme for the original floral pattern.
Source Firkin
Prismatic Geometric Tessellation Pattern 3 No Background
Source GDJ
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A bit like some carbon, or knitted netting if you will.
Source Anna Litvinuk