This one is something special. I’d call it a flat pattern, too. Very well done, sir!
Source GetDiscount
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
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
A beautiful dark padded pattern, like an old classic sofa.
Source Chris Baldie
Light gray paper pattern with small traces of fiber and some dust.
Source Atle Mo
Prismatic Abstract Geometric Background derived from an image on Pixabay.
Source GDJ
This is the remix of "Colorful Floral Pattern Background 3" uploaded by "GDJ". Thanks.
Source Yamachem
You know, tiny and sharp. I’m sure you’ll find a use for it.
Source Atle Mo
Some dark 45 degree angles creating a nice pattern. Huge.
Source Dark Sharp Edges
Vector version of a JPG that was uploaded to Pixabay by theasad121
Source Firkin
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Simple wide squares with a small indent. Fits all.
Source Petr Šulc.
Looks like an old wall. I guess that’s it then?
Source Viahorizon
Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
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
Used the 6th circle pattern designed by Viscious-Speed to create a print that can be used for card making or scrapbooking. Save as a PDF file for the best printing option.
Source Lovinglf
Background pattern made in "Grunge-Like" style. Available in both SVG and JPG formats. Edit to your needs then click the download button.
Source V. Hartikainen
As simple and subtle as it gets. But sometimes that’s just what you want.
Source Designova
A light gray background pattern with seamless fabric-like texture and almost unnoticeable stripes.
Source V. Hartikainen
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
This seamless light brown background texture resembles a wallpaper with vertical stripes. One way to use it is as a tiled background on web sites.
Source V. Hartikainen
Drawn in Paint.net and vectorised in Vector Magic
Source Firkin