Remixed from a drawing in 'Analecta Eboracensia', Thomas Widdrington, 1897.
Source Firkin
The image depicts the Japanese Edo pattern called "seigaiha" or "青海波" meaning "blue -sea- wave".I hope it's suitable for the summer season.
Source Yamachem
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i
Source Firkin
The classic 45-degree diagonal line pattern, done right.
Source Jorick van Hees
This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
Sounds like something from World of Warcraft. Has to be good.
Source Tony Kinard
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Clover with background for St. Patrick's Day. Add to a card with a doily, ribbon, a leprechaun or other embellishments.
Source BAJ
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
CC0 and seamless wellington boot pattern.
Source SliverKnight
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
Abstract Arbitrary Geometric Background derived from an image on Pixabay.
Source GDJ