I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel
Dead simple but beautiful horizontal line pattern.
Source Fabian Schultz
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A pattern drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
Background pattern made in "Grunge-Like" style. Available in both SVG and JPG formats. Edit to your needs then click the download button.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Here's a repeatable texture that resembles a light green concrete wall or something similar.
Source V. Hartikainen
Sounds French. Some 3D square diagonals, that’s all you need to know.
Source Graphiste
Feel free to use this seamless background texture as a background on a web site. It's colored in a light pink color and is seamlessly tile-able.
Source V. Hartikainen
The classic 45-degree diagonal line pattern, done right.
Source Jorick van Hees
A seamless pattern formed from miutopia's cakes on a tablecloth.
Source Firkin
This is a seamless pattern of a woody texture.The original image is here:https://pixabay.com/ja/users/ClassicallyPrinted-1302233/
Source Yamachem
Prismatic Groovy Concentric Background
Source GDJ
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Remixed from an image on Pixabay uploaded by Prawny
Source Firkin
Remixed from a drawing in 'Line and form", Walter Crane, 1914.
Source Firkin
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
A free seamless texture of reptile skin colored in a dark brown color. As always, you may use it as a repeated background image in your web design works, or for any other purposes.
Source V. Hartikainen
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin