A simple example on using clones. You can generate a nice base for a pattern fill quickly with it.
Source Lazur URH
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Simple wide squares with a small indent. Fits all.
Source Petr Šulc.
A seamless canvas texture for using as background on websites. Colored in pale tones of brown.
Source V. Hartikainen
A seamless pattern formed from a square tile based on a jpg on Pixabay. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I.
Source Firkin
A light brushed aluminum pattern for your pleasure.
Source Tim Ward
Submitted in a cream color, but you know how I like it.
Source Devin Holmes
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Background pattern originally a PNG drawn in Paint.net
Source Firkin
Prismatic Curved Diamond Pattern 5 No Background
Source GDJ
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Bright gray tones with a hint of some metal surface.
Source Hendrik Lammers
You just can’t get enough of the fabric patterns, so here is one more for your collection.
Source Krisp Designs
Zero CC Mossy stone tileable texture, photographed and made by me. CC0
Source Sojan Janso
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
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
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Sharp pixel pattern, just like the good old days.
Source Paridhi
One more in the line of patterns inspired by Japanese/Asian styles. Smooth.
Source Kim Ruddock
Zero CC tileable ground (#2) cracked, crackled texture, made by me. CC0
Source Sojan Janso
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Farmer could be some sort of fabric pattern, with a hint of green.
Source Fabian Schultz
A seamlessly repeating background pattern of wood. The image is procedurally generated, and, I think, it's turned out quite well.
Source V. Hartikainen
From a drawing in 'Picturesque New Guinea', J Lindt, 1887.
Source Firkin