The image is a seamless pattern of a fishnet.
Source Yamachem
This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
This is indeed a bit strange, but here’s to the crazy ones!
Source Christopher Buecheler
That’s what it is, a dark dot. Or sort of carbon looking.
Source Tsvetelin Nikolov
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Square design drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
Nicely crafted paper pattern, although a bit on the large side (500x593px).
Source Blaq Annabiosis
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Same as Silver Scales, but in black. Turn your site into a dragon with this great scale pattern.
Source Alex Parker
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Just like the black maze, only in light gray. Duh.
Source Peax
Psychedelic Geometric Background No Black
Source GDJ
This was formed by distorting an image of a background on Pixabay.
Source Firkin
A seamless pattern drawn originally in Paint.net by distorting a slice of background pattern 116 and copying the resulting triangle numerous times.
Source Firkin
Spice up your next school project with this icon background.
Source Swetha
Light honeycomb pattern made up of the classic hexagon shape.
Source Federica Pelzel
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
You just can’t get enough of the fabric patterns, so here is one more for your collection.
Source Krisp Designs
Prismatic Rounded Squares Grid 4 No Background
Source GDJ
This white background pattern has a seamless grunge style texture. Here's a white grunge style background pattern. Use it as a tiled background image on web sites or for other purposes.
Source V. Hartikainen
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
As simple and subtle as it gets. But sometimes that’s just what you want.
Source Designova
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
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers