An abstract texture of water. It's not perfect, but will do. You may download if you like it.
Source V. Hartikainen
A dark pattern made out of 3×3 circles and a 1px shadow. This works well as a carbon texture or background.
Source Atle Mo
You know I love paper patterns. Here is one from Stephen. Say thank you!
Source Stephen Gilbert
Submitted by DomainsInfo – wtf, right? But hey, a free pattern.
Source DomainsInfo
I’m not going to use the word Retina for all the new patterns, but it just felt right for this one. Huge wood pattern for ya’ll.
Source Atle Mo
A seamless background pattern of dark brown wood planks.
Source V. Hartikainen
Zero CC asphalt, pavement, texture, photographed and made by me. CC0 WARNING I FOUND A SEAM ON THIS TEXTURE
Source Sojan Janso
Beautiful dark noise pattern with some dust and grunge.
Source Vincent Klaiber
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
Like the name suggests, this background image consists of a pattern of dark bricks. It may be an option for you, if you are looking for something that looks like a brick wall for use as a background on web pages. It's not a masterpiece, but looks pretty nice when is tiled.
Source V. Hartikainen
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
Black & white version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
Background Wall, Art Abstract, Blue Well & CC0 texture.
Source Ractapopulous
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Zero CC tileable brick texture, photographed and made by me. CC0
Source Sojan Janso
Pattern produced in Paint.net using the Vibrato plug-in.
Source Firkin
The tile this fill pattern is based on can be had by using shift+alt+i on the rectangle.
Source Firkin
Prismatic Geometric Pattern Variation 2 With Background
Source GDJ
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
A free seamless background image with abstract texture of green "curtain".
Source V. Hartikainen
As simple and subtle as it gets. But sometimes that’s just what you want.
Source Designova
Pass parameters to the URL or edit the source code variables to configure the graph paper for the division desired.
Source JayNick
Prismatic Polka Dots 3 No Background
Source GDJ