A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
Very simple, very blu(e). Subtle and nice.
Source Seb Jachec
Prismatic Curved Diamond Pattern 5 No Background
Source GDJ
Bit of a strange name on this one, but still nice. Tiny gray square things.
Source Carlos Valdez
Zero CC tillable hard cover red book with X shape marks. Scanned and made by me.
Source Sojan Janso
Abstract Tiled Background Extended 10
Source GDJ
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
You know you can’t get enough of these linen-fabric-y patterns.
Source James Basoo
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
Derived from a drawing in 'Historiske Afhandlinger', Adolf Jorgensen, 1898.
Source Firkin
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
Not even 1kb, but very stylish. Gray thin lines.
Source Struck Axiom
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
Prismatic Isometric Cube Extra Pattern No Background
Source GDJ
Not the Rebel alliance, but a dark textured pattern.
Source Hendrik Lammers
Based on an image that was uploaded to Pixabay by devanath
Source Firkin
This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
A light gray wall or floor (you decide) of concrete.
Source Atle Mo
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Derived from an image that was uploaded to Pixabay by darkmoon1968
Source Firkin
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim