The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
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
A background tile of dark textile. Made this a long time ago and just now decided to publish it.
Source V. Hartikainen
First pattern tailor-made for Retina, with many more to come. All the old ones are upscaled, in case you want to re-download.
Source Atle Mo
This is the remix of "Tileable Wave Pattern 2" uploaded by "Arvin61r58".Thanks.I added a wire-mesh fence seamless pattern as a lower layer.
Source Yamachem
White handmade paper pattern with small bumps.
Source Marquis
Dark blue concrete wall with some small dust spots.
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
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
Prismatic Curved Diamond Pattern 8 No Background
Source GDJ
Prismatic Polyskelion Pattern No Background
Source GDJ
Here's a camo print with more tan and less green, such as might be used in a desert scenario. This is tileable, so it can be used as a wallpaper or background.
Source Eady
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Black version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
A seamless background pattern with a texture of wood planks. This wood background pattern has vertically arranged planks. You may try to rotate it 90°, to see how it will look like when the wood planks are arranged horizontally.
Source V. Hartikainen
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
One week and it's Easter already. Thought I would revisit the decorated egg contest at inkscape community: http://forum.inkscapecommunity.com/index.php?topic=118.0
Source Lazur URH
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
Sweet and subtle white plaster with hints of noise and grunge.
Source Phil Maurer
A free seamless background with pink spots.
Source V. Hartikainen
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
A seamless pattern formed from miutopia's cakes on a tablecloth.
Source Firkin
Clean and crisp lines all over the place. Wrap it up with this one.
Source Dax Kieran
A seamless pattern formed from cross 4. To get the original tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin