This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green
The image depicts the Japanese Edo pattern called "seigaiha" or "青海波" meaning "blue -sea- wave".I hope it's suitable for the summer season.
Source Yamachem
Honestly, who does not like a little pipe and mustache?
Source Luca Errico
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
Prismatic 3D Isometric Tessellation Pattern 6
Source GDJ
Carbon fiber is never out of fashion, so here is one more style for you.
Source Alfred Lee
Dark, lines, noise, tactile. You get the drift.
Source Anatoli Nicolae
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Alternative colour scheme for the original floral pattern.
Source Firkin
Prismatic Abstract Line Art Pattern Background 2
Source GDJ
Almost like little fish shells, or dragon skin.
Source Graphiste
The name alone is awesome, but so is this sweet dark pattern.
Source Federica Pelzel
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
Seamless Light Background Texture.
Source V. Hartikainen
Derived from a drawing in 'Historiske Afhandlinger', Adolf Jorgensen, 1898.
Source Firkin
Remixed from a drawing in 'A Girl in Ten Thousand', Elizabeth Meade, 1896.
Source Firkin
New paper pattern with a slightly organic feel to it, using some thin threads.
Source Atle Mo
Lovely pattern with some good-looking non-random noise lines.
Source Zucx
Use shift+alt+i on the selected rectangle in Inkscape to get the tile this is based on
Source Firkin
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 seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
You could get a bit dizzy from this one, but it might come in handy.
Source Dertig Media
Prismatic Geometric Pattern Background 2
Source GDJ
A free pink background pattern.
Source V. Hartikainen