Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i
Source Firkin
Just what the name says, paper fibers. Always good to have.
Source Heliodor jalba
Prismatic Groovy Concentric Background No Black
Source GDJ
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
A free seamless background image with abstract texture of green "curtain".
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
Formed by heavily distorting part of a an image of a fish uploaded to Pixabay by GLady
Source Firkin
This is a seamless pattern which is derived from a flower petal image.
Source Yamachem
I’m guessing this is related to the Sony Vaio? It’s a nice pattern no matter where it’s from.
Source Zigzain
A comeback for you: the popular Escheresque, now in black.
Source Patten
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Prismatic Triangular Background Design Mark II 5
Source GDJ
Simple wide squares with a small indent. Fits all.
Source Petr Šulc.
The name tells you it has curves. Oh yes, it does!
Source Peter Chon
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Dark pattern with some nice diagonal stitched lines crossing over.
Source Ashton
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
A seamless paper background texture colored in pale yellow. This seamless texture is ideal for those who need a yellow background image for their website. The texture resembles paper.
Source V. Hartikainen
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
Tweed is back in style – you heard it here first. Also, the @2X version here is great!
Source Simon Leo
Prismatic Groovy Concentric Background 4
Source GDJ