This was formed by distorting an image of a background on Pixabay.
Source Firkin
Remixed from a JPG that was uploaded to Pixabay by Osckar
Source Firkin
Lovely pattern with some good-looking non-random noise lines.
Source Zucx
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
Prismatic Groovy Concentric Background 4
Source GDJ
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
A free background tile with a pattern of pink bump dots. This background tile is sweet! Moreover, it's designed for use as website backgrounds.
Source V. Hartikainen
So tiny, just 7 by 7 pixels – but still so sexy. Ah yes.
Source Dmitriy Prodchenko
A seamlessly repeating background pattern of wood. The image is procedurally generated, and, I think, it's turned out quite well.
Source V. Hartikainen
This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
Heavily remixed from a drawing in 'Barbara Leybourne; a story of eighty years ago', Sarah Hamer, 1889.
Source Firkin
Utilising a bird from s-light and some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Derived from an image that was uploaded to Pixabay by starchim01
Source Firkin
A repeating background with a look of paper. I have added some changes to PatCreator. Now you can share your designs by submitting them to a new gallery section. Start by clicking Edit with PatCreator above.
Source V. Hartikainen
From a drawing in 'Friend or Fortune? The story of a strange year', Robert Overton, 1897.
Source Firkin
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin