Nothing like a clean set of bed sheets, huh?
Source Badhon Ebrahim
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
A brown seamless wood texture in a form of stripe pattern. The result has turned out pretty well, in my opinion.
Source V. Hartikainen
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
Classic vertical lines, in all its subtlety.
Source Cody L
CC0 and seamless wellington boot pattern.
Source SliverKnight
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
These dots are already worn for you, so you don’t have to.
Source Matt McDaniel
Floral patterns will never go out of style, so enjoy this one.
Source Lasma
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Light and tiny, just the way you like it.
Source Rohit Arun Rao
Submitted as a black pattern, I made it light and a few steps more subtle.
Source Andy
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
Prismatic Rounded Squares Grid 3 No Background
Source GDJ
Prismatic Snowflakes Pattern 2 No Background
Source GDJ
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i
Source Firkin
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra