A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman
One more brick pattern. A bit more depth to this one.
Source Benjamin Ward
Super dark, crisp and detailed. And a Kill Bill reference.
Source Badhon Ebrahim
You guessed it – looks a bit like cloth.
Source Peax Webdesign
Prismatic Rounded Squares Grid 3 No Background
Source GDJ
Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
Embossed lines and squares with subtle highlights.
Source Alex Parker
I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
This was submitted in a beige color, hence the name. Now it’s a gray paper pattern.
Source Konstantin Ivanov
From a drawing in 'Friend or Fortune? The story of a strange year', Robert Overton, 1897.
Source Firkin
Abstract Arbitrary Geometric Background derived from an image on Pixabay.
Source GDJ
Prismatic Abstract Geometric Background 4
Source GDJ
A set of paper filters. The base texture is generated the same way, only the compositing mode is varied.
Source Lazur URH
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
If you need a green background for your blog/website, try this one. Remember that Green Striped Background is seamlessly tileable.
Source V. Hartikainen
Here I have tried to create something that would look like maple wood. Not sure how well it's turned out, but at least it looks like wood.
Source V. Hartikainen
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A simple example on using clones. You can generate a nice base for a pattern fill quickly with it.
Source Lazur URH
Sort of like the Photoshop transparent background, but better!
Source Alex Parker
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
Remixed from an image that was uploaded to Pixabay by Pixeline
Source Firkin
Background Wall, Art Abstract, Watercolor Vintage style CC0 texture.
Source Ractapopulous
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso