A colourful background drawn originally in paint.net and vectorised in Vector Magic.
Source Firkin
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless pattern formed from miutopia's cakes on a tablecloth.
Source Firkin
No idea what Nistri means, but it’s a crisp little pattern nonetheless.
Source Markus Reiter
A seamless texture of a rough concrete surface.
Source V. Hartikainen
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
From drawing in 'Musings in Maoriland', Thomas Bracken, 1890.
Source Firkin
Inspired by a 1930s wallpaper pattern I saw on TV.
Source Firkin
It has waves, so make sure you don’t get sea sickness.
Source CoolPatterns
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
The texture of this background image has some similarities with leather, and it's colored in a dark brown color. So, if you are looking for a dark brown background image for your website, this may be an option for you.
Source V. Hartikainen
The image depicts a Japanese Edo pattern called "kanoko or 鹿の子" meaning "fawn" which has a fur with small white spots.
Source Yamachem
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
A comeback for you: the popular Escheresque, now in black.
Source Patten
Number five from the same submitter, makes my job easy.
Source Dima Shiper
Dead simple but beautiful horizontal line pattern.
Source Fabian Schultz
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
The image depicts a seamless pattern of the design which includes a stylized lotus and a stylized crane.I referred to the original image in a book which is into public domain.
Source Yamachem
Prismatic Curved Diamond Pattern 5 No Background
Source GDJ
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Sweet and subtle white plaster with hints of noise and grunge.
Source Phil Maurer
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua