The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
It looks like a polished stone surface to me. Download it for free, as always.
Source V. Hartikainen
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
An interesting dark spotted pattern at an angle.
Source Hendrik Lammers
Derived from an image that was uploaded to Pixabay by darkmoon1968
Source Firkin
Remixed from a drawing in 'Works. Popular edition', John Ruskin, 1886.
Source Firkin
A seamless striped fabric-like texture colored in a dark reddish brown color.
Source V. Hartikainen
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
Prismatic Rounded Squares Grid 3 No Background
Source GDJ
A large (588x375px) sand-colored pattern for your ever-growing collection. Shrink at will.
Source Alex Tapein
The name is totally random, but hey, it sounds good.
Source Atle Mo
Zero CC tileable moss or lichen covered stone texture, edited from pixabay. CC0
Source Sojan Janso
Prismatic Abstract Background Design No Black
Source GDJ
Dead simple but beautiful horizontal line pattern.
Source Fabian Schultz
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
A seamless background pattern with impressed gray dots.
Source V. Hartikainen
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
Inspired by the B&O Play, I had to make this pattern.
Source Atle Mo
Seamless Light Background Texture.
Source V. Hartikainen
More leather, and this time it’s bigger! You know, in case you need that.
Source Elemis
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
A seamless pattern formed from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Everyone loves a diamond, right? Make your site sparkle.
Source AJ Troxell
From a drawing in 'Studies for Stories', Jean Ingelow, 1864.
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin