You could get a bit dizzy from this one, but it might come in handy.
Source Dertig Media
Use shift+alt+i on the selected rectangle in Inkscape to get the tile this is based on
Source Firkin
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
Black & white version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Remixed from a drawing in 'An Index to Deering's Nottinghamia Vetus et Nova', Rupert Chicken, 1899. The unit tile can be had by selecting the rectangle in Inkscape and using shift-alt-i
Source Firkin
Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
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
Dark Tile-able Grunge Texture. I think this texture can be classified as grunge. It's free and seamless, as always.
Source V. Hartikainen
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
The original enhanced with one of Inkscapes's filters.
Source Firkin
A new one called white wall, not by me this time.
Source Yuji Honzawa
An emulated “transparent” background pattern, like that of all kinds of computer graphics software.
Source AdamStanislav
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
Dark wooden pattern, given the subtle treatment. based on texture from Cloaks.
Submitted by DomainsInfo – wtf, right? But hey, a free pattern.
Source DomainsInfo
Remixed from a drawing in 'Works. Popular edition', John Ruskin, 1886.
Source Firkin
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
A free seamless background with pink spots.
Source V. Hartikainen
The image is a design of blue glass.How about using it as background image?
Source Yamachem
This seamless light brown background texture resembles a wallpaper with vertical stripes. One way to use it is as a tiled background on web sites.
Source V. Hartikainen
Pattern produced in Paint.net using the Vibrato plug-in.
Source Firkin