From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Nasty or not, it’s a nice pattern that tiles. Like they all do.
Source Badhon Ebrahim
Some dark 45 degree angles creating a nice pattern. Huge.
Source Dark Sharp Edges
Psychedelic Geometric Background No Black
Source GDJ
To get the tile this is based on, select the rectangle in Inkscape and use 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
From a drawing in 'Az Osztrák-Magyar Monarchia irásban és képben', 1885.
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
A simple circle. That’s all it takes. This one is even transparent, for those who like that.
Source Saqib
Prismatic Abstract Geometric Background 2
Source GDJ
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Number five from the same submitter, makes my job easy.
Source Dima Shiper
The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Wild Oliva or Oliva Wilde? Darker than the others, sort of a medium dark pattern.
Source Badhon Ebrahim
Sort of like the Photoshop transparent background, but better!
Source Alex Parker
Same as Silver Scales, but in black. Turn your site into a dragon with this great scale pattern.
Source Alex Parker
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I.
Source Firkin
Abstract Stars Geometric Pattern Prismatic No Background
Source GDJ
A background pattern with wavy green vertical stripes. This one has green stripes on a white background. Download if you like it.
Source V. Hartikainen