This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
A seamless pattern formed from a rectangular tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Remixed from a JPG that was uploaded to Pixabay by Osckar
Source Firkin
It looks like a polished stone surface to me. Download it for free, as always.
Source V. Hartikainen
Prismatic Abstract Geometric Background 4 No Black
Source GDJ
Zero CC tileable hard cover red book, scanned and made by me. CC0
Source Sojan Janso
This reminds me of Game Cube. A nice light 3D cube pattern.
Source Sander Ottens
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
Prismatic Hexagonalist Pattern No Background
Source GDJ
Sort of like the back of a wooden board. Light, subtle, and stylish, just the way we like it!
Source Nikolalek
A grayscale fabric pattern with vertical lines of stitch holes.
Source V. Hartikainen
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
Honestly, who does not like a little pipe and mustache?
Source Luca Errico
A nice one indeed, but I have a feeling we have it already? If you spot a copy, let me know on Twitter.
Source Graphiste
Classic vertical lines, in all its subtlety.
Source Cody L
Tiny little flowers growing on your screen. Nice, huh?
Source Themes Tube
Medium gray fabric pattern with 45-degree lines going across.
Source Atle Mo