This one is something special. I’d call it a flat pattern, too. Very well done, sir!
Source GetDiscount
A beautiful dark wood pattern, superbly tiled.
Source Omar Alvarado
Heavily remixed from a drawing in 'Barbara Leybourne; a story of eighty years ago', Sarah Hamer, 1889.
Source Firkin
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
As simple and subtle as it gets. But sometimes that’s just what you want.
Source Designova
Prismatic Groovy Concentric Background 5 No Black
Source GDJ
More tactile goodness. This time in the form of some rough cloth.
Source Bartosz Kaszubowski
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
Fix and cc0 to get the tile this is based on.
Source SliverKnight
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Alternative colour scheme for the original floral pattern.
Source Firkin
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A bit like some carbon, or knitted netting if you will.
Source Anna Litvinuk
Prismatic Polka Dots 3 No Background
Source GDJ
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
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 formed from miutopia's cakes on a tablecloth.
Source Firkin
Sort of like the Photoshop transparent background, but better!
Source Alex Parker