Not so subtle. These tileable wood patterns are very useful.
Source Elemis
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A hint of orange color, and some crossed and embossed lines.
Source Adam Anlauf
Geometric lines are always hot, and this pattern is no exception.
Source Listvetra
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
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
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
Looks like an old wall. I guess that’s it then?
Source Viahorizon
It has waves, so make sure you don’t get sea sickness.
Source CoolPatterns
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
Prismatic Abstract Geometric Background 4 No Black
Source GDJ
Prismatic Groovy Concentric Background 5 No Black
Source GDJ
Otis Ray Redding was an American soul singer-songwriter, record producer, arranger, and talent scout. So you know.
Source Thomas Myrman
Snap! It’s a pattern, and it’s not grayscale! Of course you can always change the color in Photoshop.
Source Atle Mo
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
Here's a new gray "fabric" pattern. Use it as backgrounds for websites or for other purposes.
Source V. Hartikainen
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
Remixed from a design on Pixabay. To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
This one is quite simple in design, it consists of vertical stripes layered on top of a seamless texture.
Source V. Hartikainen
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I. Version with black background.
Source Firkin
A car pattern?! Can it be subtle? I say yes!
Source Radosław Rzepecki
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I.
Source Firkin