A seamlessly repeating background pattern of wood. The image is procedurally generated, and, I think, it's turned out quite well.
Source V. Hartikainen
A textured orange background pattern with vertical stripes.
Source V. Hartikainen
The tile can be had by using shift+alt+i on the selected rectangle in Inkscape
Source Firkin
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
A free background tile with a pattern of pink bump dots. This background tile is sweet! Moreover, it's designed for use as website backgrounds.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Zero CC tileable dry grass texture, photographed and made by me. CC0
Source Sojan Janso
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Retro Circles Background 4 No Black
Source GDJ
Dead simple but beautiful horizontal line pattern.
Source Fabian Schultz
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
You know you can’t get enough of these linen-fabric-y patterns.
Source James Basoo
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
A car pattern?! Can it be subtle? I say yes!
Source Radosław Rzepecki
A simple example on using clones. You can generate a nice base for a pattern fill quickly with it.
Source Lazur URH
Kaleidoscope Prismatic Abstract No Background
Source GDJ
White little knobs, coming in at 10x10px. Sweet!
Source Amos
ZeroCC tileable moss texture, photographed and made by me. CC0
Source Sojan Janso
The image depicts meshed silhouettes of various things.The original image is an OCAL clipart called "Enter FOSSASIA 2016 #IoT T-shirt Design Contest" uploaded by "openclipart".Thanks.
Source Yamachem
A free grid paper background pattern for using on web sites.
Source V. Hartikainen
From a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
Seamless pattern formed from a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin