This one is amazing, truly original. Go use it!
Source Viahorizon
One more sharp little tile for you. Subtle circles this time.
Source Blunia
A background pattern with wavy green vertical stripes. This one has green stripes on a white background. Download if you like it.
Source V. Hartikainen
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
This one has rusty dark brown texture.
Source V. Hartikainen
An abstract texture of black metal pipes (seamless).
Source V. Hartikainen
New paper pattern with a slightly organic feel to it, using some thin threads.
Source Atle Mo
A seamless pattern of leopard skin. It should look nice as a background element on web pages.
Source V. Hartikainen
From a drawing in 'Hyde Park from Domesday-Book to date', John Ashton, 1896.
Source Firkin
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
A large pattern with funky shapes and form. An original. Sort of origami-ish.
Source Luuk van Baars
Same classic 45-degree pattern, dark version.
Source Luke McDonald
Greyscale version of a pattern that came out of playing with the 'slinky' plug-in for Paint.net
Source Firkin
Turn your site into a dragon with this great scale pattern.
Source Alex Parker
Number five from the same submitter, makes my job easy.
Source Dima Shiper
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Derived from a PNG that was uploaded to Pixabay by nutkitten
Source Firkin
Zero CC tileable pine bark texture, photographed and made by me. CC0
Source Sojan Janso
Remixed from a drawing in 'A Girl in Ten Thousand', Elizabeth Meade, 1896.
Source Firkin