This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Lovely pattern with splattered vintage speckles.
Source David Pomfret
A bit strange this one, but nice at the same time.
Source Diogo Silva
A bit strange this one, but nice at the same time.
Source Diogo Silva
This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'Two Women in the Klondike', Mary Hitchcock, 1899.
Source Firkin
One week and it's Easter already. Thought I would revisit the decorated egg contest at inkscape community: http://forum.inkscapecommunity.com/index.php?topic=118.0
Source Lazur URH
This is lovely, just the right amount of subtle noise, lines and textures.
Source Richard Tabor
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A subtle shadowed checkered pattern. Increase the lightness for even more subtle sexiness.
Source Josh Green
A car pattern?! Can it be subtle? I say yes!
Source Radosław Rzepecki
The image depicts a tiled seamless pattern.The tile represents four leaves aligned every 90 ° , which may look like a bird or a dragon .The original leaf design is from a Japanese old book.
Source Yamachem
8 by 8 pixels, and just what the title says.
Source pixilated
This is the remix of "polka dot seamless pattern".The image depicts polka dot seamless pattern.
Source Yamachem
This one is amazing, truly original. Go use it!
Source Viahorizon
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
Derived from an image that was uploaded to Pixabay by TheDigitalArtist
Source Firkin
A free seamless background texture that looks like a brown stone wall.
Source V. Hartikainen