This is so subtle you need to bring your magnifier!
Source Carlos Valdez
The following repeating website background is colored in a blue gray color and resembles a concrete wall or something similar to it.
Source V. Hartikainen
Gold Triangular Seamless Pattern No Background
Source GDJ
An abstract pale yellow paper-like background with stains colored in yellow and green.
Source V. Hartikainen
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Colour version of the original pattern.
Source Firkin
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
Zero CC tileable grass texture, photographed and made by me. CC0
Source Sojan Janso
Zero CC tileable ground (#2) cracked, crackled texture, made by me. CC0
Source Sojan Janso
Prismatic Isometric Cube Wireframe Pattern No Background
Source GDJ
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
Here's a bluish gray striped background pattern for use on web sites.
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A bit like smudged paint or some sort of steel, here is scribble light.
Source Tegan Male
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Number 4 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Prismatic Curved Diamond Pattern No Background
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
A dark pattern made out of 3×3 circles and a 1px shadow. This works well as a carbon texture or background.
Source Atle Mo
It looks very nice I think.
Source V. Hartikainen
A hint of orange color, and some crossed and embossed lines.
Source Adam Anlauf
Remixed from a drawing in 'Analecta Eboracensia', Thomas Widdrington, 1897.
Source Firkin
The image is a remix of "edo pattern-samekomon".I changed the color of dots from black to white and added BG in light-yellow.
Source Yamachem
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Prismatic Snowflakes Pattern 3 No Background
Source GDJ