Geometric triangles seem to be quite hot these days.
Source Pixeden
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Sounds French. Some 3D square diagonals, that’s all you need to know.
Source Graphiste
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
The image depicts an edo-era pattern called "same-komon" or "鮫小紋"which looks like a shark skin.The "same" in Japanese means shark in English.
Source Yamachem
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
Formed by distorting a JPG from PublicDomainPictures
Source Firkin
Number 5 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
An aged paper background tile with smeared and pressed text.
Source V. Hartikainen
Could remind you a bit of those squares in Super Mario Bros, yeh?
Source Jeff Wall
Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.
Source Atle Mo
Remixed from a drawing in 'Analecta Eboracensia', Thomas Widdrington, 1897.
Source Firkin
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
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
Here's a new paper-like background for free use on personal and commercial projects (this applies to all background patterns here).
Source V. Hartikainen
Number 4 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Neat little photography icon pattern.
Source Hossam Elbialy
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Sort of reminds me of those old house wallpapers.
Source Tish
Prismatic Abstract Line Art Pattern Background
Source GDJ
An alternative colour scheme to the original seamless pattern.
Source Firkin