A good starting point for a cardboard pattern. This would work well in a variety of colors.
Source Atle Mo
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
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
Retro Circles Background 5 No Black
Source GDJ
This was formed by distorting an image of a background on Pixabay.
Source Firkin
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Based on an image that was uploaded to Pixabay by devanath
Source Firkin
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Background Wall, Art Abstract, Watercolor Vintage style CC0 texture.
Source Ractapopulous
There are many carbon patterns, but this one is tiny.
Source Designova
Prismatic Polka Dots Mark II 2 No Background
Source GDJ
A seamless pattern based on a rectangular tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Here's a new background image for websites with a seamless pink texture. It should look beautiful with website themes where light pink background is needed. The background is seamless, therefore it should be used as a tiled background.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Dark blue concrete wall with some small dust spots.
Source Atle Mo
Bumps, highlight and shadows – all good things.
Source Badhon Ebrahim
Prismatic Rounded Squares Grid 4 No Background
Source GDJ