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
Prismatic Groovy Concentric Background
Source GDJ
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
This one is quite simple in design, it consists of vertical stripes layered on top of a seamless texture.
Source V. Hartikainen
The image depicts a seamless pattern of a tortoise in tortoiseshell (hexagon).
Source Yamachem
Tiny, tiny 3D cubes. Reminds me of the good old pattern from k10k.
Source Etienne Rallion
Seamless Green Tile Background
Source V. Hartikainen
This is the remix of "polka dot seamless pattern".The image depicts polka dot seamless pattern.
Source Yamachem
A seamless dark leather-like background texture with diagonal lines that look like stitches.
Source V. Hartikainen
Abstract Ellipses Background Grayscale
Source GDJ
Feel free to use this seamless background texture as a background on a web site. It's colored in a light pink color and is seamlessly tile-able.
Source V. Hartikainen
Zero CC tileable hard cover green book, scanned and made by me. CC0
Source Sojan Janso
The image depicts a seamless pattern of a Japanese family crest called "chidori" in Japanese .A chidori in Japanese means a plover in English.
Source Yamachem
Prismatic Polka Dots Mark II No Background
Source GDJ
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
More in the paper realm, this time with fibers.
Source Jorge Fuentes
A free background tile with a pattern of pink bump dots. This background tile is sweet! Moreover, it's designed for use as website backgrounds.
Source V. Hartikainen
The tile this is formed from can be retrieved in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
I have no idea how to describe this one, but it’s light and delicate.
Source JBasoo
Remixed from an image on Pixabay uploaded by Prawny
Source Firkin
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
Fix side and a seamless pattern formed from circles.
Source SliverKnight
Prismatic Geometric Pattern Variation 2 With Background
Source GDJ