Sounds French. Some 3D square diagonals, that’s all you need to know.
Source Graphiste
This is so subtle you need to bring your magnifier!
Source Carlos Valdez
Paper pattern with small dust particles and 45-degree strokes.
Source Atle Mo
Derived from a PNG that was uploaded to Pixabay by nutkitten
Source Firkin
Alternative colour scheme. Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prismatic Rounded Squares Grid 3 No Background
Source GDJ
Zero CC tileable bark texture, photographed and made by me. CC0
Source Sojan Janso
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
Light gray grunge wall with a nice texture overlay.
Source Adam Anlauf
An alternative colour scheme to the original seamless pattern.
Source Firkin
From an image on opengameart.org shared by rubberduck.
Source Firkin
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
This is the remix of an Openclipart clipart called "Maze" uploaded by "any_ono_mous".Thanks.This is a seamless pattern of a maze.
Source Yamachem
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
A simple but elegant classic. Every collection needs one of these.
Source Christopher Burton
Prismatic Abstract Geometric Background 2
Source GDJ
This light background pattern has a texture of "frozen" surface with diagonal stripes. Here's an yet another addition to the collection of free website backgrounds.
Source V. Hartikainen
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
A repeating background of beige paper with vintage look. Repeats to infinity, as usual.
Source V. Hartikainen