CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Prismatic Groovy Concentric Background 4
Source GDJ
A seamless pattern based on a rectangular tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A rusty grunge background for websites. Feel free to use it in your site's theme.
Source V. Hartikainen
I love cream! 50x50px and lovely in all the good ways.
Source Thomas Myrman
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
The tile this is formed from can be retrieved in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
Remixed from a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
Prismatic 3D Isometric Tessellation Pattern 6
Source GDJ
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868
Source Firkin
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
Detailed but still subtle and quite original. Lovely gray shades.
Source Kim Ruddock
An abstract pale yellow paper-like background with stains colored in yellow and green.
Source V. Hartikainen
Remixed from a PNG that was uploaded to Pixabay by gingertea
Source Firkin
Paper model of a tetrahedron. Modelo de papel de um tetraedro.
Source laobc
First pattern tailor-made for Retina, with many more to come. All the old ones are upscaled, in case you want to re-download.
Source Atle Mo