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
Prismatic Hexagonalist Pattern No Background
Source GDJ
Sort of like the Photoshop transparent background, but better!
Source Alex Parker
You could get a bit dizzy from this one, but it might come in handy.
Source Dertig Media
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
This one needs to be used in small areas; you can see it repeat.
Source Luca
Green Web Background, Seamless tile.
Source V. Hartikainen
Colour version of the original pattern.
Source Firkin
A seamless pattern formed from miutopia's cakes on a tablecloth.
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
Derived from an image that was uploaded to Pixabay by mdmelo.
Source Firkin
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Prismatic Hypnotic Pattern No Background
Source GDJ
From a drawing in 'Storia del Palazzo Vecchio in Firenze', Aurelio Gotti, 1889.
Source Firkin
To get the tile this is made up from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A pale yellow background pattern with vertical stripes. The stripes are partially faded. I think this background image turned out pretty well, especially those faded stripes.
Source V. Hartikainen
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin