This ons is quite old school looking. Retro, even. I like it.
Source Arno Declercq
The classic 45-degree diagonal line pattern, done right.
Source Jorick van Hees
A free pink background pattern.
Source V. Hartikainen
Abstract Arbitrary Geometric Background derived from an image on Pixabay.
Source GDJ
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
This is the remix of an OCAL clipart called "Art Nouveau ornament" uploaded by "microcosme".Thanks.This is a seamless pattern of an Art Nouveau ornament.
Source Yamachem
A rusty grunge background for websites. Feel free to use it in your site's theme.
Source V. Hartikainen
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I. A version of the original with random colors.
Source Firkin
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
The perfect pattern for all your blogs about type, or type-related matters.
Source Atle Mo
Same as gray sand but lighter. A sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
Prismatic Curved Diamond Pattern 4 No Background
Source GDJ
A colourful background drawn originally in paint.net and vectorised in Vector Magic.
Source Firkin
I have no idea what J Boo means by this name, but hey – it’s hot.
Source j Boo
One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
It’s an egg, in the form of a pattern. This really is 2012.
Source Paul Phönixweiß
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