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
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
One more updated pattern. Not really carbon fiber, but it’s the most popular pattern, so I’ll give you an extra choice.
Source Atle Mo
So tiny, just 7 by 7 pixels – but still so sexy. Ah yes.
Source Dmitriy Prodchenko
Zero CC tileable Crackled Cement (streaks) texture, photographed and made by me. CC0
Source Sojan Janso
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Black And White Floral Pattern Background from PDP.
Source GDJ
Paper pattern with small dust particles and 45-degree strokes.
Source Atle Mo
Dark, lines, noise, tactile. You get the drift.
Source Anatoli Nicolae
Feel free to download this "Dark Wood" background texture for your web site. The background tiles seamlessly!
Source V. Hartikainen
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
The image depicts a seamless pattern made using a bird's face.
Source Yamachem
Colour version of the original pattern.
Source Firkin
Prismatic Abstract Line Art Pattern Background
Source GDJ
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
A seamless pattern of dark bricks. Maybe it's not very realistic, but it looks good in my opinion.
Source V. Hartikainen
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
An emulated “transparent” background pattern, like that of all kinds of computer graphics software.
Source AdamStanislav
Number 1 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos