There are quite a few grid patterns, but this one is a super tiny grid with some dust for good measure.
Source Dominik Kiss
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
The texture of this background image has some similarities with leather, and it's colored in a dark brown color. So, if you are looking for a dark brown background image for your website, this may be an option for you.
Source V. Hartikainen
Seamless Olive Green Web Background Image
Source V. Hartikainen
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
A seamless pattern with wide vertical stripes colored in pale yellow.
Source V. Hartikainen
Alternative colour scheme for the original floral pattern.
Source Firkin
A seamless background pattern of dark brown wood planks.
Source V. Hartikainen
Mostly just mucked about with the colours and made one of the paths in the lead frame opaque. The glass remains transparent.
Source Firkin
This is the remix of an OCAL clipart called "Rain on Window" uploaded by "pagarmidna".Thanks.This is a seamless pattern of raindrops.
Source Yamachem
Number 4 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
A beautiful dark padded pattern, like an old classic sofa.
Source Chris Baldie
Because I love dark patterns, here is Brushed Alum in a dark coating.
Source Tim Ward
Tiny circle waves, almost like the ocean.
Source Sagive
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
ZeroCC tileable beechwood wood texture, generated in Neo Texture Edit by me. CC0
Source Sojan Janso
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
A seamlessly tile-able grunge background image.
Source V. Hartikainen
A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
High detail stone wall with minor cracks and specks.
Source Projecteightyfive
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning