A free green background pattern with a pattern of rhombuses on a seamless texture. Feel free to use it as a tiled background image on your web site.
Source V. Hartikainen
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
Not the most creative name, but it’s a good all-purpose light background.
Source Dmitry
Sharp pixel pattern, just like the good old days.
Source Paridhi
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Derived from an image that was uploaded to Pixabay by darkmoon1968
Source Firkin
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
Remixed from a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Seamless pattern made from a tile that can be obtained in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Lovely pattern with some good-looking non-random noise lines.
Source Zucx
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
A free pink background pattern.
Source V. Hartikainen
Alternative colour scheme. 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
A free seamless background texture of "timber wall" (colored in dark brown).
Source V. Hartikainen
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
Prismatic Isometric Cube Wireframe Pattern No Background
Source GDJ
This is a grid, only it’s noisy. You know. Reminds you of those printed grids you draw on.
Source Vectorpile
Because I love dark patterns, here is Brushed Alum in a dark coating.
Source Tim Ward
New paper pattern with a slightly organic feel to it, using some thin threads.
Source Atle Mo