Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
From a design in 'Storia del Palazzo Vecchio in Firenze', Aurelio Gotti, 1889.
Source Firkin
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Uses spirals from Pixabay. To get the basic tile select the rectangle in Inkscape and use shift+alt+i
Source Firkin
Might not be super subtle, but quite original in its form.
Source Alex Smith
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A pattern derived from repeating unit cells each derived from part of a mosaic in paint.net. The starting point for the mosaic was a picture of some prawns!
Source Firkin
Prismatic Curved Diamond Pattern 5 No Background
Source GDJ
Prismatic Snowflakes Pattern No Background
Source GDJ
Pixel by pixel, sharp and clean. Very light pattern with clear lines.
Source M.Ashok
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
This seamless light brown background texture resembles a wallpaper with vertical stripes. One way to use it is as a tiled background on web sites.
Source V. Hartikainen
A repeatable image with dark background and metal grid pattern.
Source V. Hartikainen
From an image on opengameart.org shared by rubberduck.
Source Firkin
Farmer could be some sort of fabric pattern, with a hint of green.
Source Fabian Schultz
Prismatic Groovy Concentric Background 3
Source GDJ
This background pattern has futuristic look. So, maybe it could be used on websites or blogs dedicated to video games?!
Source V. Hartikainen
It’s okay to be square! A nice light gray pattern with random squares.
Source Waseem Dahman
Remixed from a JPG that was uploaded to Pixabay by theasad121
Source Firkin
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
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
I love these crisp, tiny, super subtle patterns.
Source Badhon Ebrahim
Same classic 45-degree pattern, dark version.
Source Luke McDonald
Orange-red pattern for tiled backgrounds.
Source V. Hartikainen
Prismatic Abstract Background Design No Black
Source GDJ
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin