Because I love dark patterns, here is Brushed Alum in a dark coating.
Source Tim Ward
Black And White Floral Pattern Background Inverse
Source GDJ
Number 2 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
It’s a hole, in a pattern. On your website. Dig it!
Source Josh Green
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
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
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Fix and cc0 to get the tile this is based on.
Source SliverKnight
Farmer could be some sort of fabric pattern, with a hint of green.
Source Fabian Schultz
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
ZeroCC tileable stone texture, edited from pixabay. CC0
Source Sojan Janso
Dark, lines, noise, tactile. You get the drift.
Source Anatoli Nicolae
Black brick wall pattern. Brick your site up!
Source Alex Parker
Looks as if it's spray painted on the wall. You can be sure that this pattern will seamlessly fill your backgrounds on web pages.
Source V. Hartikainen
A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
You could get a bit dizzy from this one, but it might come in handy.
Source Dertig Media
This background pattern contains worn out colorful stripes as a texture.
Source V. Hartikainen
Uses spirals from Pixabay. To get the basic tile select the rectangle in Inkscape and use shift+alt+i
Source Firkin
Prismatic Curved Diamond Pattern 4 No Background
Source GDJ
It’s an egg, in the form of a pattern. This really is 2012.
Source Paul Phönixweiß
Super simple but very nice indeed. Gray with vertical stripes.
Source Merrin Macleod
Seamless Background For Websites. It has a texture similar to cork-board.
Source V. Hartikainen