Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Super dark, crisp and detailed. And a Kill Bill reference.
Source Badhon Ebrahim
CC0 remixed from a drawing. Walter Crane, 1914, Firkin.
Source SliverKnight
From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.
Source Firkin
A free seamless background image with abstract texture of green "curtain".
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
Remixed from an image on Pixabay uploaded by Prawny
Source Firkin
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
This background pattern contains a seamless texture of bark. It's not very realistic, but I think it looks quite nice.
Source V. Hartikainen
An alternative colour scheme to the original seamless pattern.
Source Firkin
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
A bit like smudged paint or some sort of steel, here is scribble light.
Source Tegan Male
A pattern drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
A good starting point for a cardboard pattern. This would work well in a variety of colors.
Source Atle Mo
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
Prismatic Hexagonalism Pattern No Background
Source GDJ
Same as Silver Scales, but in black. Turn your site into a dragon with this great scale pattern.
Source Alex Parker
Heavily remixed from a drawing that was uploaded to Pixabay by ractapopulous
Source Firkin