Inspired by this, I came up with this pattern. Madness!
Source Atle Mo
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Prismatic Abstract Geometric Background 4
Source GDJ
An interesting dark spotted pattern at an angle.
Source Hendrik Lammers
Prismatic Snowflakes Pattern 2 No Background
Source GDJ
This beige background pattern resembles a concrete wall with engravings or something similar to it.
Source V. Hartikainen
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
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 celebrate the new feature, we need some sparkling diamonds.
Source Atle Mo
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
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A repeating background of thick textured paper. Actually, it turned out to look like something between a paper and fabric.
Source V. Hartikainen
Prismatic Curved Diamond Pattern 8 No 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