Because I love dark patterns, here is Brushed Alum in a dark coating.
Source Tim Ward
This was formed by distorting an image of a background on Pixabay.
Source Firkin
The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
Remixed from an image on Pixabay uploaded by Prawny
Source Firkin
Prismatic Isometric Cube Wireframe Pattern No Background
Source GDJ
Sounds like something from World of Warcraft. Has to be good.
Source Tony Kinard
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Another fairly simple design drawn in Paint.net and vectorized in Inkscape.
Source Firkin
A new one called white wall, not by me this time.
Source Yuji Honzawa
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857
Source Firkin
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
A seamless dark leather-like background texture with diagonal lines that look like stitches.
Source V. Hartikainen
Thin lines, noise and texture creates this crisp dark denim pattern.
Source Marco Slooten
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Background pattern originally a PNG drawn in Paint.net
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless marble-like texture colored in light blue.
Source V. Hartikainen
Green Background Pattern
Source V. Hartikainen
This was formed by distorting an image of a background on Pixabay.
Source Firkin
The image is a seamless pattern of a fishnet.
Source Yamachem
These dots are already worn for you, so you don’t have to.
Source Matt McDaniel