Background pattern 270 #2061
Dark CC 0A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
More Textures
Diamond pattern (colour 8) #2273
Red CC 0From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Arches #715
Light CC BY-SA 3.0One more in the line of patterns inspired by Japanese/Asian styles. Smooth.
Source Kim Ruddock
Hexellence@2X #706
Light CC BY-SA 3.0Detailed but still subtle and quite original. Lovely gray shades.
Source Kim Ruddock
Gloomy Stripes #994
Stripes CC BY-SA 3.0A dark striped seamless pattern suitable for use as a background on websites.
Source V. Hartikainen
Decorative divider 228 #2154
Dark CC 0Remixed from a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
Tessellation 16 (colour 5) #2211
Yellow CC 0The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Dark Blue Gray Wallpaper Texture #901
Stripes CC BY-SA 3.0This seamless background image should look nice on websites. It has a dark blue gray texture with vertical stripes, it tiles seamlessly and, like all of the background images here, it's free. So, if you like it, take it!
Source V. Hartikainen
Decorative divider #1962
Dark CC 0From a drawing in 'A Life Interest', Mrs Alexander, 1888.
Source Firkin
Rough Diagonal #691
Fabric CC BY-SA 3.0The classic 45-degree diagonal line pattern, done right.
Source Jorick van Hees