From a drawing in 'A Guide to the Guildhall of the City of London', John Baddeley, 1898.
Source Firkin
Prismatic Abstract Background Design No Black
Source GDJ
A seamless pattern formed from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
A seamless background texture of old cardboard.
Source V. Hartikainen
One can never have too few rice paper patterns, so here is one more.
Source Atle Mo
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A seamless striped fabric-like texture colored in a dark reddish brown color.
Source V. Hartikainen
Nicely crafted paper pattern, although a bit on the large side (500x593px).
Source Blaq Annabiosis
Same classic 45-degree pattern, dark version.
Source Luke McDonald
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Prismatic Triangular Background Design Mark II 5
Source GDJ
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Nasty or not, it’s a nice pattern that tiles. Like they all do.
Source Badhon Ebrahim
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Geometric Tessellation Pattern No Background
Source GDJ
Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
Feel free to download this "Dark Wood" background texture for your web site. The background tiles seamlessly!
Source V. Hartikainen
Subtle scratches on a light gray background.
Source Andrey Ovcharov
Remixed from a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Number five from the same submitter, makes my job easy.
Source Dima Shiper
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
Black paper texture, based on two different images.
Source Atle Mo
Based from Design Kindle