The tile this fill pattern is based on can be had by using shift+alt+i on the rectangle.
Source Firkin
This seamless light brown background texture resembles a wallpaper with vertical stripes. One way to use it is as a tiled background on web sites.
Source V. Hartikainen
Zero CC tileable bark texture, photographed and made by me. CC0
Source Sojan Janso
It looks like a polished stone surface to me. Download it for free, as always.
Source V. Hartikainen
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
I have no idea what J Boo means by this name, but hey – it’s hot.
Source j Boo
Prismatic Polka Dots 3 No Background
Source GDJ
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
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
A seamlessly repeating background pattern of wood. The image is procedurally generated, and, I think, it's turned out quite well.
Source V. Hartikainen
This is the remix of "Background pattern 115" uploaded by "Firkin".Thanks.
Source Yamachem
Prepared mostly as a raster in Paint.net and vectorised.
Source Firkin
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
The file was named striped lens, but hey – Translucent Fibres works too.
Source Angelica
From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.
Source Firkin
Zero CC tillable hard cover red book with X shape marks. Scanned and made by me.
Source Sojan Janso
Background formed from the iconic plastic construction bricks that gave me endless hours of fun when I was a lad.
Source Firkin
Sometimes you just need the simplest thing.
Source Fabricio
More in the paper realm, this time with fibers.
Source Jorge Fuentes
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
White circles connecting on a light gray background.
Source Mark Collins