Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Greyscale version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
This is indeed a bit strange, but here’s to the crazy ones!
Source Christopher Buecheler
A seamless pattern of dark bricks. Maybe it's not very realistic, but it looks good in my opinion.
Source V. Hartikainen
Zero CC tileable bark texture, photographed and made by me. CC0
Source Sojan Janso
A seamless striped fabric-like texture colored in a dark reddish brown color.
Source V. Hartikainen
Have you wondered about how it feels to be buried alive? Here is the pattern for it.
Source Hendrik Lammers
Submitted in a cream color, but you know how I like it.
Source Devin Holmes
From a drawing in 'Danmarks Riges Historie af J. Steenstrup, Kr. Erslev, A. Heise, V. Mollerup, J. A. Fridericia, E. Holm, A. D. Jørgensen', 1897.
Source Firkin
A very dark spotted twinkle pattern for your twinkle needs.
Source Badhon Ebrahim
Remixed from an image that was uploaded to Pixabay by Pixeline
Source Firkin
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Remixed from a drawing that was uploaded to Pixabay by ractapopulous
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Clean and crisp lines all over the place. Wrap it up with this one.
Source Dax Kieran
This one looks like a cork panel. Feel free to use it as a tiled background on your blog or website.
Source V. Hartikainen
A re-make of the Gradient Squares pattern.
Source Dimitar Karaytchev
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
Remixed from a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
Prismatic Groovy Concentric Background
Source GDJ