This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Light gray paper pattern with small traces of fiber and some dust.
Source Atle Mo
It has waves, so make sure you don’t get sea sickness.
Source CoolPatterns
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
This is lovely, just the right amount of subtle noise, lines and textures.
Source Richard Tabor
It’s like Shine Dotted’s sister, only rotated 45 degrees.
Source mediumidee
Colour version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A bit of scratched up grayness. Always good.
Source Dmitry
Feel free to download and use it, or see the rest of the dark background patterns that I have made. Anyway, I hope you will find something that you like.
Source V. Hartikainen
Wild Oliva or Oliva Wilde? Darker than the others, sort of a medium dark pattern.
Source Badhon Ebrahim
Retro Circles Background 8 No Black
Source GDJ
This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
Alternative colour scheme. Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Derived from a drawing in 'The Murmur of the Shells', Samuel Cowen, 1879.
Source Firkin
Prismatic Triangular Background Design Mark II 5
Source GDJ
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
This seamless web background texture looks like gray stone. It's great for using as a background image on web pages, or on some of their elements. Anyway, I hope you will find use for it.
Source V. Hartikainen
Super detailed 16×16 tile that forms a beautiful pattern of straws.
Source Pavel
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
A very dark asfalt pattern based off of a photo taken with my iPhone.
Source Atle Mo