This seamless pattern consists of a blue grid on a yellow background.
Source V. Hartikainen
Could be paper, could be a Polaroid frame – up to you!
Source Chaos
Prismatic Triangular Seamless Pattern III With Background
Source GDJ
ZeroCC tileable mossy (lichen) stone texture, edited from pixabay. CC0
Source Sojan Janso
Remixed from a drawing in 'Jezebel's Daughter', Wilkie Collins 1880
Source Firkin
Inspired by the B&O Play, I had to make this pattern.
Source Atle Mo
Prismatic Hypnotic Pattern No Background
Source GDJ
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Snap! It’s a pattern, and it’s not grayscale! Of course you can always change the color in Photoshop.
Source Atle Mo
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Remixed from a JPG that was uploaded to Pixabay by Osckar
Source Firkin
A slightly grainy paper pattern with small horizontal and vertical strokes.
Source Atle Mo
Abstract Tiled Background Extended 12
Source GDJ
Might not be super subtle, but quite original in its form.
Source Alex Smith
Heavily remixed from a drawing in 'Barbara Leybourne; a story of eighty years ago', Sarah Hamer, 1889.
Source Firkin
Lovely pattern with splattered vintage speckles.
Source David Pomfret
Dark, square, clean and tidy. What more can you ask for?
Source Jaromír Kavan
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
Here's a brown background pattern with subtle stripes. I hope you'll like the color. If not, feel free to change it using an image editor, if you know how of course. Personally, I'm using GIMP to create these backgrounds.
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
Lovely light gray floral motif with some subtle shades.
Source GraphicsWall
A version without colours blended together to give a different look.
Source Firkin
From an image on opengameart.org shared by rubberduck.
Source Firkin
Nice little grid. Would work great as a base on top of some other patterns.
Source Arno Gregorian