The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Abstract Tiled Background Extended 8
Source GDJ
I have no idea what J Boo means by this name, but hey – it’s hot.
Source j Boo
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
Traced from a drawing in 'Household Stories from the Collection of the Brothers Grimm', Wilhelm Carl Grimm , 1882.
Source Firkin
Looks like an old rug or a computer chip.
Source Patutin Sergey
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Zero CC tileable Crackled Cement (streaks) texture, photographed and made by me. CC0
Source Sojan Janso
Prismatic Curved Diamond Pattern 5 No Background
Source GDJ
I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
Dark Tile-able Grunge Texture. I think this texture can be classified as grunge. It's free and seamless, as always.
Source V. Hartikainen
If you’re sick of the fancy 3D, grunge and noisy patterns, take a look at this flat 2D brick wall.
Source Listvetra
A subtle shadowed checkered pattern. Increase the lightness for even more subtle sexiness.
Source Josh Green
Derived from a drawing in 'Elfrica. An historical romance of the twelfth century', Charlotte Boger, 1885
Source Firkin
Free tiled background with colorful stripes and white splatter.
Source V. Hartikainen
I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
Prismatic Curved Diamond Pattern 2 No Background
Source GDJ
The image is a seamless pattern of a fishnet.
Source Yamachem
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
Inspired by a pattern seen on a public domain image of a very old tile. To get the unit cell, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Your eyes can trip a bit from looking at this – use it wisely.
Source Michal Chovanec
Zero CC tileable hard cover green book, scanned and made by me. CC0
Source Sojan Janso