Sounds French. Some 3D square diagonals, that’s all you need to know.
Source Graphiste
Your eyes can trip a bit from looking at this – use it wisely.
Source Michal Chovanec
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
The image depicts a seamless pattern of a Japanese family crest called "chidori" in Japanese .A chidori in Japanese means a plover in English.
Source Yamachem
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
One more sharp little tile for you. Subtle circles this time.
Source Blunia
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
Not sure if this is related to the Nami you get in Google image search, but hey, it’s nice!
Source Dertig Media
One more brick pattern. A bit more depth to this one.
Source Benjamin Ward
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
An interesting dark spotted pattern at an angle.
Source Hendrik Lammers
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.
Source Firkin
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
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
This is a remix of "blue wave-seigaiha".I hope this subtle color version of Seigaiha would be suitable for background .
Source Yamachem
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Abstract Geometric Background 4 No Black
Source GDJ