Actually, there's no clouds in it, but I think it looks quite nice.
Source V. Hartikainen
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
Classic 45-degree pattern, light version.
Source Luke McDonald
Colour version of the original seamless pattern.
Source Firkin
From an image on opengameart.org shared by rubberduck.
Source Firkin
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
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
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
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
Zero CC tileable cork floor, photographed and made by me. CC0
Source Sojan Janso
Zero CC tileable hard cover green book, scanned and made by me. CC0
Source Sojan Janso
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
Sharp pixel pattern looking like some sort of fabric.
Source Dmitry
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
I love these crisp, tiny, super subtle patterns.
Source Badhon Ebrahim
A beautiful dark wood pattern, superbly tiled.
Source Omar Alvarado
A seamless pattern formed from a rectangular tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Remixed from an image that was uploaded to Pixabay by CatherineClennan
Source Firkin
A grayscale fabric pattern with vertical lines of stitch holes.
Source V. Hartikainen
A fun-looking elastoplast/band-aid pattern. A hint of orange tone in this one.
Source Josh Green
Feel free to use this seamless background texture as a background on a web site. It's colored in a light pink color and is seamlessly tile-able.
Source V. Hartikainen
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ