Abstract Tiled Background Extended 10
Source GDJ
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
Just like the black maze, only in light gray. Duh.
Source Peax
The tile this fill pattern is based on can be had by using shift+alt+i on the rectangle.
Source Firkin
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 canvas texture for using as background on websites. Colored in pale tones of brown.
Source V. Hartikainen
Remix from a drawing in 'Ostatnie chwile powstania styczniowego', Zygmunt Sulima, 1887.
Source Firkin
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua