The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
Light gray pattern with an almost wall tile-like appearance.
Source Markus Tinner
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
Snap! It’s a pattern, and it’s not grayscale! Of course you can always change the color in Photoshop.
Source Atle Mo
Used a cherry by doctormo to make this seamless pattern
Source Firkin
Dark Tile-able Grunge Texture. I think this texture can be classified as grunge. It's free and seamless, as always.
Source V. Hartikainen
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Light gray grunge wall with a nice texture overlay.
Source Adam Anlauf
Abstract Ellipses Background Grayscale
Source GDJ
Floral patterns might not be the hottest thing right now, but you never know when you need it!
Source Lauren
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
A pattern derived from part of a fractal rendering in Paint.net.
Source Firkin
Coming in at 666x666px, this is an evil big pattern, but nice and soft at the same time.
Source Atle Mo
Prismatic Abstract Geometric Background derived from an image on Pixabay.
Source GDJ
A seamless background texture of old cardboard.
Source V. Hartikainen
The tile can be had by selecting the rectangle in Inkscape and using shift+alt+i. Remixed from a drawing in 'Flowers of Song', Frederick Weatherly, 1895.
Source Firkin
Sharp pixel pattern looking like some sort of fabric.
Source Dmitry
A good starting point for a cardboard pattern. This would work well in a variety of colors.
Source Atle Mo
It’s an egg, in the form of a pattern. This really is 2012.
Source Paul Phönixweiß
Sort of reminds me of those old house wallpapers.
Source Tish
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Inspired by a pattern found in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Abstract Ellipses Background Grayscale
Source GDJ
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin