Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
A comeback for you: the popular Escheresque, now in black.
Source Patten
Prismatic Isometric Cube Extra Pattern No Background
Source GDJ
Prismatic Isometric Cube Wireframe Pattern No Background
Source GDJ
It’s like Shine Dotted’s sister, only rotated 45 degrees.
Source mediumidee
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
The following repeating website background is colored in a blue gray color and resembles a concrete wall or something similar to it.
Source V. Hartikainen
You were craving more leather, so I whipped this up by scanning a leather jacket.
Source Atle Mo
Three shades of gray makes this pattern look like a small carbon fiber surface. Great readability even for small fonts.
Source Atle Mo
It’s a hole, in a pattern. On your website. Dig it!
Source Josh Green
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
A free seamless background texture that looks like a brown stone wall.
Source V. Hartikainen
Lovely pattern with some good-looking non-random noise lines.
Source Zucx
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Non-seamless pattern drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
A free grid paper background pattern for using on web sites.
Source V. Hartikainen
Not even 1kb, but very stylish. Gray thin lines.
Source Struck Axiom
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin
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
A background pattern with wavy green vertical stripes. This one has green stripes on a white background. Download if you like it.
Source V. Hartikainen
A seamless marble-like texture colored in light blue.
Source V. Hartikainen
Redrawn based on a drawing in 'По Сѣверо-Западу Россіи' Konstantin Sluchevsky, 1897.
Source Firkin
A pattern drawn in Paint.net and vectorized in Vector Magic.
Source Firkin