This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A re-make of the Gradient Squares pattern.
Source Dimitar Karaytchev
A background pattern with a look of rough fabric.
Source V. Hartikainen
emixed from a JPG that was uploaded to Pixabay by Kyotime
Source Firkin
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
Might not be super subtle, but quite original in its form.
Source Alex Smith
From a drawing in 'Az Osztrák-Magyar Monarchia irásban és képben', 1885.
Source Firkin
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
Light gray pattern with an almost wall tile-like appearance.
Source Markus Tinner
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
One more sharp little tile for you. Subtle circles this time.
Source Blunia
Subtle scratches on a light gray background.
Source Andrey Ovcharov
Prismatic Curved Diamond Pattern 5 No Background
Source GDJ
A seamless pale yellow paper background with a pattern of animal tracks.
Source V. Hartikainen
Could remind you a bit of those squares in Super Mario Bros, yeh?
Source Jeff Wall
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Fix side and a seamless pattern formed from circles.
Source SliverKnight
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
High detail stone wall with minor cracks and specks.
Source Projecteightyfive
Remixed from a drawing in 'Hungary. A guide book. By several authors', 1890.
Source Firkin
Found on the ground in french cafe in kunming, Yunnan, china
Source Rejon
If you don’t like cream and pixels, you’re in the wrong place.
Source Mizanur Rahman