CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
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
Can never have too many knitting patterns, especially as nice as this.
Source Victoria Spahn
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
Coming in at 666x666px, this is an evil big pattern, but nice and soft at the same time.
Source Atle Mo
Prismatic Polyskelion Pattern No Background
Source GDJ
Very simple, very blu(e). Subtle and nice.
Source Seb Jachec
The name is totally random, but hey, it sounds good.
Source Atle Mo
From a drawing in 'Friend or Fortune? The story of a strange year', Robert Overton, 1897.
Source Firkin
Wild Oliva or Oliva Wilde? Darker than the others, sort of a medium dark pattern.
Source Badhon Ebrahim
A background pattern with wavy green vertical stripes. This one has green stripes on a white background. Download if you like it.
Source V. Hartikainen
Zero CC tileable wood texture, made by me procedurally in Neo Texture Edit.
Source Sojan Janso
The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A seamless web texture with illustration of pale color stains on canvas.
Source V. Hartikainen
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Here's a quite bright pink background pattern for use on websites. It doesn't look like a real fur, but it definitely resembles one.
Source V. Hartikainen
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen