From a design in 'Storia del Palazzo Vecchio in Firenze', Aurelio Gotti, 1889.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
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
This is so subtle you need to bring your magnifier!
Source Carlos Valdez
Prismatic Rounded Squares Grid 4 No Background
Source GDJ
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
Zero CC tileable dry grass texture, photographed and made by me. CC0
Source Sojan Janso
Might not be super subtle, but quite original in its form.
Source Alex Smith
A seamless canvas texture for using as background on websites. Colored in pale tones of brown.
Source V. Hartikainen
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
A seamless pattern with wide vertical stripes colored in pale yellow.
Source V. Hartikainen
Prismatic Groovy Concentric Background 4
Source GDJ
Just the symbols of the signs of the zodiac distributed in a chequer board-like pattern
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
Not sure if this is related to the Nami you get in Google image search, but hey, it’s nice!
Source Dertig Media
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
Pattern that came out of playing with the 'slinky' plug-in for Paint.net
Source Firkin
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
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