You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
Seamless Green Tile Background
Source V. Hartikainen
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A simple but elegant classic. Every collection needs one of these.
Source Christopher Burton
A rusty grunge background for websites. Feel free to use it in your site's theme.
Source V. Hartikainen
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
This background texture resembles stone. It may be used as a background on web pages or on some of their html elements (header, borders, menu bar, etc.). Just modify it for your needs.
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
Retro Circles Background 4 No Black
Source GDJ
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
Like the name suggests, this background image consists of a pattern of dark bricks. It may be an option for you, if you are looking for something that looks like a brick wall for use as a background on web pages. It's not a masterpiece, but looks pretty nice when is tiled.
Source V. Hartikainen
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
You guessed it – looks a bit like cloth.
Source Peax Webdesign
Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
"Beige Stone", Tileable Texture.
Source V. Hartikainen
It looks like a polished stone surface to me. Download it for free, as always.
Source V. Hartikainen
A free seamless background image with abstract texture of green "curtain".
Source V. Hartikainen
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Turn your site into a dragon with this great scale pattern.
Source Alex Parker
Prismatic Snowflakes Pattern 3 No Background
Source GDJ
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua