It looks like a polished stone surface to me. Download it for free, as always.
Source V. Hartikainen
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
A pale yellow background pattern with vertical stripes. The stripes are partially faded. I think this background image turned out pretty well, especially those faded stripes.
Source V. Hartikainen
Prismatic Groovy Concentric Background No Black
Source GDJ
The following free background pattern has glossy diagonal stripes as a texture to it, and it's colored in a light blue gray color. This background pattern is suitable for using in web design or any other graphic design projects. This applies to all background patterns here.
Source V. Hartikainen
Clean and crisp lines all over the place. Wrap it up with this one.
Source Dax Kieran
Zero CC tileable seed texture, edited by me to be seamless from a Pixabay image. CC0
Source Sojan Janso
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
This metal background pattern resembles a metal plate with rivets. Solid rivets on a metal plate.
Source V. Hartikainen
Same as the black version, but now in shades of gray. Very subtle and fine grained.
Source Atle Mo
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Groovy Concentric Background No Black
Source GDJ
A seamless paper background texture colored in pale yellow. This seamless texture is ideal for those who need a yellow background image for their website. The texture resembles paper.
Source V. Hartikainen
A criss-cross pattern similar to one I saw mown into a sports field.
Source Firkin
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
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
Zero CC tileable grass texture, photographed and made by me. CC0
Source Sojan Janso
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Sort of like the Photoshop transparent background, but better!
Source Alex Parker
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin