A comeback for you: the popular Escheresque, now in black.
Source Patten
Greyscale version of a pattern that came out of playing with the 'slinky' plug-in for Paint.net
Source Firkin
Used correctly, this could be nice. Used in a bad way, all hell will break loose.
Source Atle Mo
A dark metallic background with a pattern of stamped dots. Here's a dark "metallic" background pattern for you.
Source V. Hartikainen
A free pink background pattern.
Source V. Hartikainen
Floral patterns might not be the hottest thing right now, but you never know when you need it!
Source Lauren
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
With a name like this, it has to be hot. Diagonal lines in light shades.
Source Isaac
The classic notebook paper with horizontal stripes.
Source Are Sundnes
Adapted from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Hey, you never know when you’ll need a bird pattern, right?
Source Pete Fecteau
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
This yellow background consists of a pattern of glossy gold buttons arranged in polka dot style on a seamless texture. Here's a pale yellow background pattern. Feel free to use it for your needs!
Source V. Hartikainen
This ladies and gentlemen, is texturetastic! Love it.
Source Adam Pickering
Feel free to download this "Dark Wood" background texture for your web site. The background tiles seamlessly!
Source V. Hartikainen
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
The image is a remix of "edo pattern-samekomon".I changed the color of dots from black to white and added BG in light-yellow.
Source Yamachem
Prismatic Abstract Geometric Background 5
Source GDJ
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo