Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A seamless dark leather-like background texture with diagonal lines that look like stitches.
Source V. Hartikainen
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
Remixed from an image that was uploaded to Pixabay by Pixeline
Source Firkin
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
This background image has seamless texture that resembles a surface of gray stone.
Source V. Hartikainen
Colour version of the original pattern inspired by the front cover of 'Old and New Paris', Henry Edwards, 1894.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Polyskelion Pattern No Background
Source GDJ
The image depicts a seamless pattern which was made using stripe-like things including borders.I used OCAL cliparts called "Blue Greek Key With Lines Border" uploaded by "GR8DAN" and "daisy border" uploaded by "johnny_automatic".Thanks.
Source Yamachem
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Washi (和紙?) is a type of paper made in Japan. Here’s the pattern for you!
Source Carolynne
From a drawing of the coat of arms of the Ottoman Empire on Wikimedia.
Source Firkin
The Grid. A digital frontier. I tried to picture clusters of information as they traveled through the computer.
Source Haris Šumić
Prismatic Geometric Tessellation Pattern No Background
Source GDJ
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
A slightly grainy paper pattern with small horizontal and vertical strokes.
Source Atle Mo
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
Here's a subtle marble-like background for use on websites.
Source V. Hartikainen
This background has abstract texture with some similarities to wood.
Source V. Hartikainen