Psychedelic #745
Gray CC BY-SA 3.0Geometric triangles seem to be quite hot these days.
Source Pixeden
More Textures
Background Patterns - Aubergine #247
Fabric CC 0If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
Background pattern 314 #1839
Yellow CC 0The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Part of Bayeux Tapestry 3 #2448
Noise CC 0From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
Hoffman #1152
Wall CC BY-SA 3.0Did anyone say The Hoff? This pattern is in no way related to Baywatch.
Source Josh Green
Colourful background 32 #2173
Colorful CC 0Colourful background achieved with gradient fills.
Source Firkin
Background pattern 266 #2068
Dark CC 0Remixed from a drawing in 'Some account of the Worshipful Company of Ironmongers', John Nicholl, 1866.
Source Firkin
"Beige Wall", Tileable Background #1189
Concrete CC BY-SA 3.0This beige background pattern resembles a concrete wall with engravings or something similar to it.
Source V. Hartikainen
Seamless Texture of Wood Planks #880
Wood CC BY-SA 3.0Here's an yet another background for websites, with a seamless texture of wood planks this time.
Source V. Hartikainen
Background pattern 306 (colour 5) #1879
Colorful CC 0Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Prismatic Abstract Geometric Background 4 #271
Noise CC 0Prismatic Abstract Geometric Background 4
Source GDJ
Dark Tile-able Grunge Texture #1123
Grunge CC BY-SA 3.0Dark Tile-able Grunge Texture. I think this texture can be classified as grunge. It's free and seamless, as always.
Source V. Hartikainen
Dark Mosaic #121
Dark CC BY-SA 3.0Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
Triangular #1156
Gray CC BY-SA 3.0Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
Aged Grid Paper Background #1072
Paper CC BY-SA 3.0A seamless web background with texture of aged grid paper.
Source V. Hartikainen
Debut Dark #1014
Dark CC BY-SA 3.0Same classic 45-degree pattern, dark version.
Source Luke McDonald
Textured Orange Stripe Pattern #997
Stripes CC BY-SA 3.0A textured orange background pattern with vertical stripes.
Source V. Hartikainen
Txture #757
Dark CC BY-SA 3.0Dark, lines, noise, tactile. You get the drift.
Source Anatoli Nicolae
Polaroid #187
Wall CC BY-SA 3.0Smooth Polaroid pattern with a light blue tint.
Source Daniel Beaton