Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
A black tile-able background with paper-like texture.
Source V. Hartikainen
This is the remix of "Colorful Floral Pattern Background 3" uploaded by "GDJ". Thanks.
Source Yamachem
White fabric looking texture with some nice random wave features.
Source Hendrik Lammers
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
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Element of beach pattern with background.
Source Rones
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
f you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
Might not be super subtle, but quite original in its form.
Source Alex Smith
A repeating background of beige paper with vintage look. Repeats to infinity, as usual.
Source V. Hartikainen
The image depicts the Japanese Edo pattern called "seigaiha" or "青海波" meaning "blue -sea- wave".I hope it's suitable for the summer season.
Source Yamachem
A gray background pattern with a texture of textile. Suits perfectly for web design.
Source V. Hartikainen
Prismatic Rounded Squares Grid 4 No Background
Source GDJ
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Uses spirals from Pixabay. To get the basic tile select the rectangle in Inkscape and use shift+alt+i
Source Firkin
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
ZeroCC tileabel stone granite texture, edited from pixabay. CC0
Source Sojan Janso
A brown seamless wood texture in a form of stripe pattern. The result has turned out pretty well, in my opinion.
Source V. Hartikainen
This is the remix of "Background pattern 115" uploaded by "Firkin".Thanks.
Source Yamachem
More leather, and this time it’s bigger! You know, in case you need that.
Source Elemis
I’m starting to think I have a concrete wall fetish.
Source Atle Mo
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin