Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
A bit like smudged paint or some sort of steel, here is scribble light.
Source Tegan Male
Just the symbols of the signs of the zodiac distributed in a chequer board-like pattern
Source Firkin
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
The image depicts a seamless pattern of a tortoise in tortoiseshell (hexagon).
Source Yamachem
Bit of a strange name on this one, but still nice. Tiny gray square things.
Source Carlos Valdez
Geometric triangles seem to be quite hot these days.
Source Pixeden
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
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i
Source Firkin
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i
Source Firkin
Alternative colour scheme for the original floral pattern.
Source Firkin
Prismatic Abstract Background Design No Black
Source GDJ
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
Kaleidoscope Prismatic Abstract No Background
Source GDJ
Everyone loves a diamond, right? Make your site sparkle.
Source AJ Troxell
Background Wall, Art Abstract, Watercolor Vintage style CC0 texture.
Source Ractapopulous
Prismatic Abstract Background Design No Black
Source GDJ
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A free seamless background with pink spots.
Source V. Hartikainen
From a drawing in 'La Principauté de Liège et les Pays-Bas au XVIe siècle', Société des Bibliophiles Liégeois ,1887.
Source Firkin