A good starting point for a cardboard pattern. This would work well in a variety of colors.
Source Atle Mo
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers
It’s a hole, in a pattern. On your website. Dig it!
Source Josh Green
Fake or not, it’s quite luxurious.
Source Factorio.us Collective
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
The texture of this background image has some similarities with leather, and it's colored in a dark brown color. So, if you are looking for a dark brown background image for your website, this may be an option for you.
Source V. Hartikainen
Colored maple leaves scattered on a surface. This is tileable, so it can be used as a background or wallpaper.
Source Eady
Sharp pixel pattern, just like the good old days.
Source Paridhi
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
Derived from an image that was uploaded to Pixabay by Kaz
Source Firkin
This is a remix of "geometrical pattern 01".
Source Yamachem
This was formed by distorting an image of a background on Pixabay.
Source Firkin
ZeroCC tileable beechwood wood texture, generated in Neo Texture Edit by me. CC0
Source Sojan Janso
Prismatic Floral Pattern 3 Variation 3 No Background
Source GDJ
A white version of the very popular linen pattern.
Source Ant Ekşiler
Derived from a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
There are many carbon patterns, but this one is tiny.
Source Designova