Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
This is sort of fresh, but still feels a bit old school.
Source Martuchox
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
Everyone needs some stardust. Sprinkle it on your next project.
Source Atle Mo
Love me some light mesh on a Monday. Sharp.
Source Wilmotte Bastien
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
This background texture resembles stone. It may be used as a background on web pages or on some of their html elements (header, borders, menu bar, etc.). Just modify it for your needs.
Source V. Hartikainen
A light gray fabric pattern with faded vertical stripes.
Source V. Hartikainen
A dark pattern made out of 3×3 circles and a 1px shadow. This works well as a carbon texture or background.
Source Atle Mo
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
This was formed by distorting an image of a background on Pixabay.
Source Firkin
A version without colours blended together to give a different look.
Source Firkin
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
There are many carbon patterns, but this one is tiny.
Source Designova
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A repeatable image with dark background and metal grid pattern.
Source V. Hartikainen
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Everyone loves a diamond, right? Make your site sparkle.
Source AJ Troxell
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
Prismatic Snowflakes Pattern No Background
Source GDJ
Prismatic Chevrons Pattern 5 With Background
Source GDJ
A seamless pattern created from a square tile. To get the tile, select the pattern in Inkscape and use shift+alt+i.
Source Firkin