A good starting point for a cardboard pattern. This would work well in a variety of colors.
Source Atle Mo
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Prismatic Abstract Line Art Pattern Background
Source GDJ
Prismatic Isometric Cube Wireframe Pattern No Background
Source GDJ
Here's a brown background pattern with subtle stripes. I hope you'll like the color. If not, feel free to change it using an image editor, if you know how of course. Personally, I'm using GIMP to create these backgrounds.
Source V. Hartikainen
A seamless pattern the starting point for which was a 'colour modulo' texture in Paint.net.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
That’s what it is, a dark dot. Or sort of carbon looking.
Source Tsvetelin Nikolov
Geometric triangles seem to be quite hot these days.
Source Pixeden
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Not even 1kb, but very stylish. Gray thin lines.
Source Struck Axiom
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A seamless paper background colored in pale yellow.
Source V. Hartikainen
Just the symbols of the signs of the zodiac distributed in a chequer board-like pattern
Source Firkin
Snap! It’s a pattern, and it’s not grayscale! Of course you can always change the color in Photoshop.
Source Atle Mo
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
Just like your old suit, all striped and smooth.
Source Alex Berkowitz
This background pattern contains a texture of yellow wood planks. I think it looks quite original.
Source V. Hartikainen