Zero CC tileable hard cover green book, scanned and made by me. CC0
Source Sojan Janso
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
The classic 45-degree diagonal line pattern, done right.
Source Jorick van Hees
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
It was called Navy Blue, but I made it dark. You know, the way I like it.
Source Ethan Hamilton
This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Bright gray tones with a hint of some metal surface.
Source Hendrik Lammers
Remixed from a design on Pixabay. To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
A fun-looking elastoplast/band-aid pattern. A hint of orange tone in this one.
Source Josh Green
Derived from a PNG that was uploaded to Pixabay by nutkitten
Source Firkin
A bit like some carbon, or knitted netting if you will.
Source Anna Litvinuk
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
There are many carbon patterns, but this one is tiny.
Source Designova
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
Luxurious looking pattern (for a T-shirt maybe?) with a hint of green.
Source Simon Meek
A heavy hitter at 400x400px, but lovely still.
Source Breezi