A bit simplified version. Although it could be edited out to be simpler. Anyway, this time the tiling is converted to a pattern fill -which is using clipping for the tile's edges.
Source Lazur URH
Background Wall, Art Abstract, white Well & CC0 texture.
Source Ractapopulous
Medium gray fabric pattern with 45-degree lines going across.
Source Atle Mo
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
From a drawing in 'Cassell's Library of English Literature', Henry Morley, 1883.
Source Firkin
Beautiful dark noise pattern with some dust and grunge.
Source Vincent Klaiber
Honestly, who does not like a little pipe and mustache?
Source Luca Errico
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Zero CC tileable pine bark texture, photographed and made by me. CC0
Source Sojan Janso
This reminds me of Game Cube. A nice light 3D cube pattern.
Source Sander Ottens
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
This is a remix of "flower seamless pattern".I rotated the original image by 90 degrees.This is a seamless pattern of flowers.These horizontal wavy lines are one of Edo patterns which is called "tatewaku or tachiwaku or 立湧" that represents uprising steam or vapor.
Source Yamachem
If you’re sick of the fancy 3D, grunge and noisy patterns, take a look at this flat 2D brick wall.
Source Listvetra
Inspired by a drawing in 'Kulturgeschichte', Freidrich Hellwald, 1896.
Source Firkin
Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
From a drawing in 'Heroes of North African Discovery', Nancy Meugens, 1894.
Source Firkin
Prismatic Abstract Geometric Background 3
Source GDJ
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
The base gradient edited so now more details are rendered.
Source Lazur URH
A light gray wall or floor (you decide) of concrete.
Source Atle Mo