Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
A free background pattern with abstract green tiles.
Source V. Hartikainen
Like the name suggests, this background image consists of a pattern of dark bricks. It may be an option for you, if you are looking for something that looks like a brick wall for use as a background on web pages. It's not a masterpiece, but looks pretty nice when is tiled.
Source V. Hartikainen
An abstract texture of black metal pipes (seamless).
Source V. Hartikainen
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
Clean and crisp lines all over the place. Wrap it up with this one.
Source Dax Kieran
A seamless pattern with wide vertical stripes colored in pale yellow.
Source V. Hartikainen
Colour version of the original pattern.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i
Source Firkin
From a drawing in 'Hubert Montreuil, or the Huguenot and the Dragoon', Francisca Ouvry, 1873.
Source Firkin
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A seamlessly tile-able grunge background image.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i
Source Firkin
Coming in at 666x666px, this is an evil big pattern, but nice and soft at the same time.
Source Atle Mo
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
This was submitted in a beige color, hence the name. Now it’s a gray paper pattern.
Source Konstantin Ivanov
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Zero CC tileable pine bark texture, photographed and made by me. CC0
Source Sojan Janso
The edges of all the red objects line up either vertically or horizontally, but it doesn't appear so. Made from a square tile that can be got by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin