A seamless background tile of aged paper with shabby look.
Source V. Hartikainen
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
Dark, square, clean and tidy. What more can you ask for?
Source Jaromír Kavan
The Grid. A digital frontier. I tried to picture clusters of information as they traveled through the computer.
Source Haris Šumić
Colored maple leaves scattered on a surface. This is tileable, so it can be used as a background or wallpaper.
Source Eady
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
A free seamless background image with abstract texture of green "curtain".
Source V. Hartikainen
Paper pattern with small dust particles and 45-degree strokes.
Source Atle Mo
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
Bright gray tones with a hint of some metal surface.
Source Hendrik Lammers
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Prismatic Groovy Concentric Background 5 No Black
Source GDJ
A light gray fabric pattern with faded vertical stripes.
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Same classic 45-degree pattern, dark version.
Source Luke McDonald
From a drawing in 'Bond Slaves. The story of a struggle.', Isabella Varley, 1893.
Source Firkin
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin