Black brick wall pattern. Brick your site up!
Source Alex Parker
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
Colourful background achieved with gradient fills.
Source Firkin
A light gray wall or floor (you decide) of concrete.
Source Atle Mo
Alternative colour scheme. Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
You may use it as is, or modify it as you like.
Source V. Hartikainen
Prismatic Abstract Line Art Pattern Background 2
Source GDJ
Utilising a bird from s-light and some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Turn your site into a dragon with this great scale pattern.
Source Alex Parker
Oh yes, it happened! A pattern in full color.
Source Atle Mo
Prismatic Snowflakes Pattern 3 No Background
Source GDJ
The tile this is formed from can be retrieved in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
Did some testing with Repper Pro tonight, and this gray mid-tone pattern came out.
Source Atle Mo
A seamless pattern formed from a sports car on clker.com. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Zero CC tileable moss or lichen covered stone texture, edited from pixabay. CC0
Source Sojan Janso
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua