From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
From a drawing in 'Cassell's Library of English Literature', Henry Morley, 1883.
Source Firkin
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
One more in the line of patterns inspired by Japanese/Asian styles. Smooth.
Source Kim Ruddock
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i
Source Firkin
It’s an egg, in the form of a pattern. This really is 2012.
Source Paul Phönixweiß
Vertical lines with a bumpy, yet crisp, feel to it.
Source Raasa
Prismatic Chevrons Pattern 5 With Background
Source GDJ
A bit like smudged paint or some sort of steel, here is scribble light.
Source Tegan Male
A comeback for you: the popular Escheresque, now in black.
Source Patten
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
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
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
Prismatic Polyskelion Pattern No Background
Source GDJ
From a design in 'Storia del Palazzo Vecchio in Firenze', Aurelio Gotti, 1889.
Source Firkin