The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
A free seamless background texture that looks like a brown stone wall.
Source V. Hartikainen
Colour version of the original pattern.
Source Firkin
A free seamless background texture of "timber wall" (colored in dark brown).
Source V. Hartikainen
A black tile-able background with paper-like texture.
Source V. Hartikainen
Submitted by DomainsInfo – wtf, right? But hey, a free pattern.
Source DomainsInfo
Paper pattern with small dust particles and 45-degree strokes.
Source Atle Mo
Number 5 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Looks like an old wall. I guess that’s it then?
Source Viahorizon
If you don’t like cream and pixels, you’re in the wrong place.
Source Mizanur Rahman
You know you can’t get enough of these linen-fabric-y patterns.
Source James Basoo
Turn your site into a dragon with this great scale pattern.
Source Alex Parker
Zero CC tileable hard cover red book, scanned and made by me. CC0
Source Sojan Janso
Seamless pattern formed from a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso