Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
One can never have too few rice paper patterns, so here is one more.
Source Atle Mo
Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
Heavily remixed from a drawing in 'Barbara Leybourne; a story of eighty years ago', Sarah Hamer, 1889.
Source Firkin
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I.
Source Firkin
Nice little grid. Would work great as a base on top of some other patterns.
Source Arno Gregorian
Snap! It’s a pattern, and it’s not grayscale! Of course you can always change the color in Photoshop.
Source Atle Mo
The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Continuing the geometric trend, here is one more.
Source Mike Warner
Zero CC bark from fur tree tileable texture, photographed and made by me. CC0
Source Sojan Janso
Background formed from the iconic plastic construction bricks that gave me endless hours of fun when I was a lad.
Source Firkin
Someone was asking about how to achieve a fur pattern at #inkscape irc so tried to make a filter on it. Flood filled fractal noises rigged together. May someone find a good use for these.
Source Lazur URH
If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
Remixed from a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Prismatic Curved Diamond Pattern 6 No Background
Source GDJ
Actually remixed from a pattern on Pixabay. But then noticed a very similar one on Openclipart.org uploaded by btj51q2.
Source Firkin
Turn your site into a dragon with this great scale pattern.
Source Alex Parker
Remixed from a drawing in 'Analecta Eboracensia', Thomas Widdrington, 1897.
Source Firkin