ZeroCC tileable moss texture, photographed and made by me. CC0
Source Sojan Janso
Inspired by a pattern found in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A dark background pattern/texture of a dimpled metal plate.
Source V. Hartikainen
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Here's a bluish gray striped background pattern for use on web sites.
Source V. Hartikainen
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
One can never have too few rice paper patterns, so here is one more.
Source Atle Mo
The starting point for this was a texture drawn with the 'Radial Colors' plug-in in Paint.net.
Source Firkin
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Remixed from a drawing in 'Очерки Русской Исторіи въ памятникахъ быта', Petr Polevoi, 1879.
Source Firkin
Beautiful dark noise pattern with some dust and grunge.
Source Vincent Klaiber
Dark blue concrete wall with some small dust spots.
Source Atle Mo
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
A seamless web texture with illustration of pale color stains on canvas.
Source V. Hartikainen
There are many carbon patterns, but this one is tiny.
Source Designova
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
An alternative colour scheme for the original seamless texture formed from an image on Pixabay.
Source Firkin
Retro Circles Background 8 No Black
Source GDJ
Here's an yet another background for websites, with a seamless texture of wood planks this time.
Source V. Hartikainen
A repeating background with wood/straw like texture.
Source V. Hartikainen
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prismatic Curved Diamond Pattern 6 No Background
Source GDJ