A background formed from an image of an old tile on the New York Metropolitan Museum of Art website. To get the base tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
That’s what it is, a dark dot. Or sort of carbon looking.
Source Tsvetelin Nikolov
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Here's an yet another background for websites, with a seamless texture of wood planks this time.
Source V. Hartikainen
Turn your site into a dragon with this great scale pattern.
Source Alex Parker
With a name like this, it has to be hot. Diagonal lines in light shades.
Source Isaac
Hexagonal dark 3D pattern. What more can you ask for?
Source Norbert Levajsics
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
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 seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
ZeroCC tileable beechwood wood texture, generated in Neo Texture Edit by me. CC0
Source Sojan Janso
Prismatic Abstract Background Design
Source GDJ
Prismatic Groovy Concentric Background 4
Source GDJ
This makes me wanna shoot some pool! Sweet green pool table pattern.
Source Caveman
From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Free tiled background with colorful stripes and white splatter.
Source V. Hartikainen
Prismatic Triangular Background Design Mark II 5
Source GDJ
Zero CC tileable hard cover cells book texture, 4k, scanned and made by me. CC0
Source Sojan Janso
Geometric triangles seem to be quite hot these days.
Source Pixeden