Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
This pattern comes in orange, and it looks as if it is "made of glass".
Source V. Hartikainen
A seamless pattern of dark bricks. Maybe it's not very realistic, but it looks good in my opinion.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i
Source Firkin
Abstract Tiled Background Extended 10
Source GDJ
Inspired by this, I came up with this pattern. Madness!
Source Atle Mo
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Dark pattern with some nice diagonal stitched lines crossing over.
Source Ashton
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
From a drawing in 'A Rolling Stone. A tale of wrongs and revenge', John Hartley, 1878.
Source Firkin
Background Wall, Art Abstract, Blue Well & CC0 texture.
Source Ractapopulous
A seamlessly repeating background pattern of wood. The image is procedurally generated, and, I think, it's turned out quite well.
Source V. Hartikainen
Derived from an image that was uploaded to Pixabay by darkmoon1968
Source Firkin
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Continuing the geometric trend, here is one more.
Source Mike Warner
The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin