The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Redrawn based on a drawing in 'По Сѣверо-Западу Россіи' Konstantin Sluchevsky, 1897.
Source Firkin
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Scanned some rice paper and tiled it up for you. Enjoy.
Source Atle Mo
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić
Embossed lines and squares with subtle highlights.
Source Alex Parker
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
You know you can’t get enough of these linen-fabric-y patterns.
Source James Basoo
One more in the line of patterns inspired by Japanese/Asian styles. Smooth.
Source Kim Ruddock
Here's a seamless brown cork board background texture. Feel free to download or reshare if you like.
Source V. Hartikainen
A seamless pattern formed from a modified version of rwwgub's tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A free pink background pattern.
Source V. Hartikainen
Bright Multicolored Floral Background by Karen Arnold from PDP.
Source GDJ
Prismatic Abstract Background Design No Black
Source GDJ
A dark metal plate with an embossed grid pattern and a bit of rust. Here's a dark metal plate texture for use as a tiled background on web pages.
Source V. Hartikainen
The file was named striped lens, but hey – Translucent Fibres works too.
Source Angelica
Zero CC tileable wood texture, made by me procedurally in Neo Texture Edit.
Source Sojan Janso
Mostly just mucked about with the colours and made one of the paths in the lead frame opaque. The glass remains transparent.
Source Firkin