Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
I have no idea how to describe this one, but it’s light and delicate.
Source JBasoo
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
The image depicts a seamless pattern of a Japanese family crest called "chidori" in Japanese .A chidori in Japanese means a plover in English.
Source Yamachem
You may use it as is, or modify it as you like.
Source V. Hartikainen
This background texture resembles stone. It may be used as a background on web pages or on some of their html elements (header, borders, menu bar, etc.). Just modify it for your needs.
Source V. Hartikainen
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Remixed from a drawing in 'Hungary. A guide book. By several authors', 1890.
Source Firkin
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
An abstract pale yellow paper-like background with stains colored in yellow and green.
Source V. Hartikainen
Submitted as a black pattern, I made it light and a few steps more subtle.
Source Andy
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
Sharp pixel pattern, just like the good old days.
Source Paridhi
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Love me some light mesh on a Monday. Sharp.
Source Wilmotte Bastien
Nicely crafted paper pattern, although a bit on the large side (500x593px).
Source Blaq Annabiosis
Detailed but still subtle and quite original. Lovely gray shades.
Source Kim Ruddock
A pale yellow background pattern with vertical stripes. The stripes are partially faded. I think this background image turned out pretty well, especially those faded stripes.
Source V. Hartikainen
Wild Oliva or Oliva Wilde? Darker than the others, sort of a medium dark pattern.
Source Badhon Ebrahim
A background pattern with a look of rough fabric.
Source V. Hartikainen
Not so subtle. These tileable wood patterns are very useful.
Source Elemis
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin