It looks like a polished stone surface to me. Download it for free, as always.
Source V. Hartikainen
Light honeycomb pattern made up of the classic hexagon shape.
Source Federica Pelzel
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
A background pattern with green vertical stripes. A new striped background pattern. This time a green one.
Source V. Hartikainen
Remixed from an image that was uploaded to Pixabay by Pixeline
Source Firkin
The original enhanced with one of Inkscapes's filters.
Source Firkin
Remixed from a design on Pixabay. To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green
A seamless pattern of leopard skin. It should look nice as a background element on web pages.
Source V. Hartikainen
This light background pattern has a texture of "frozen" surface with diagonal stripes. Here's an yet another addition to the collection of free website backgrounds.
Source V. Hartikainen
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
From a drawing in 'A Rolling Stone. A tale of wrongs and revenge', John Hartley, 1878.
Source Firkin
I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
Fake or not, it’s quite luxurious.
Source Factorio.us Collective
This makes me wanna shoot some pool! Sweet green pool table pattern.
Source Caveman
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Floral patterns might not be the hottest thing right now, but you never know when you need it!
Source Lauren
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady