From a drawing in 'Cassell's Library of English Literature', Henry Morley, 1883.
Source Firkin
Prismatic Abstract Geometric Background 5
Source GDJ
Can never have too many knitting patterns, especially as nice as this.
Source Victoria Spahn
Subtle scratches on a light gray background.
Source Andrey Ovcharov
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Formed by heavily distorting part of a an image of a fish uploaded to Pixabay by GLady
Source Firkin
Like the name suggests, this background image consists of a pattern of dark bricks. It may be an option for you, if you are looking for something that looks like a brick wall for use as a background on web pages. It's not a masterpiece, but looks pretty nice when is tiled.
Source V. Hartikainen
By popular request, an outline version of the pentagon pattern.
Source Atle Mo
The tile this is formed from can be retrieved in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
A very dark asfalt pattern based off of a photo taken with my iPhone.
Source Atle Mo
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
A version without colours blended together to give a different look.
Source Firkin
A seamless pattern formed from a modified version of rwwgub's tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
That’s what it is, a dark dot. Or sort of carbon looking.
Source Tsvetelin Nikolov
A bit simplified version. Although it could be edited out to be simpler. Anyway, this time the tiling is converted to a pattern fill -which is using clipping for the tile's edges.
Source Lazur URH
This background image has seamless texture that resembles a surface of gray stone.
Source V. Hartikainen
Dark, crisp and subtle. Tiny black lines on top of some noise.
Source Wilmotte Bastien