This seamless background image should look nice on websites. It has a dark blue gray texture with vertical stripes, it tiles seamlessly and, like all of the background images here, it's free. So, if you like it, take it!
Source V. Hartikainen
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
Not even 1kb, but very stylish. Gray thin lines.
Source Struck Axiom
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
This one looks like a cork panel. Feel free to use it as a tiled background on your blog or website.
Source V. Hartikainen
A background formed from an image of an old tile on the New York Metropolitan Museum of Art website. To get the base tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Awesome name, great pattern. Who does not love space?
Source Nick Batchelor
An aged paper background tile with smeared and pressed text.
Source V. Hartikainen
This is so subtle you need to bring your magnifier!
Source Carlos Valdez
Here's a quite bright pink background pattern for use on websites. It doesn't look like a real fur, but it definitely resembles one.
Source V. Hartikainen
Seamless tile drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Love me some light mesh on a Monday. Sharp.
Source Wilmotte Bastien
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Washi (和紙?) is a type of paper made in Japan. Here’s the pattern for you!
Source Carolynne
Honestly, who does not like a little pipe and mustache?
Source Luca Errico
No, not the band but the pattern. Simple squares in gray tones, of course.
Source Atle Mo
Hey, you never know when you’ll need a bird pattern, right?
Source Pete Fecteau
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
Remixed from a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin