You know I’m a sucker for these. Well-crafted paper pattern.
Source Mihaela Hinayon
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
From a drawing in 'Az Osztrák-Magyar Monarchia irásban és képben', 1885.
Source Firkin
This one is amazing, truly original. Go use it!
Source Viahorizon
Background Wall, Art Abstract, Blue Well & CC0 texture.
Source Ractapopulous
Bit of a strange name on this one, but still nice. Tiny gray square things.
Source Carlos Valdez
Square design drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Alternative colour scheme. Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
An abstract web texture of a polished blue stone (or does it look more like ice).
Source V. Hartikainen
Prismatic Curved Diamond Pattern 4 No Background
Source GDJ
Prismatic Groovy Concentric Background 5
Source GDJ
Washi (和紙?) is a type of paper made in Japan. Here’s the pattern for you!
Source Carolynne
Prismatic Isometric Cube Extra Pattern No Background
Source GDJ
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
To get the tile this is made up from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Seamless Green Tile Background
Source V. Hartikainen
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
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
Abstract Tiled Background Extended 10
Source GDJ