Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
A slightly grainy paper pattern with small horizontal and vertical strokes.
Source Atle Mo
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Inspired by a pattern I saw in a 19th century book. This seamless pattern was created from a square tile. To get the tile, select the pattern in Inkscape and use shift+alt+i.
Source Firkin
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Zero CC tileable ground (#2) cracked, crackled texture, made by me. CC0
Source Sojan Janso
A repeating background for websites with a texture of black groove stripes.
Source V. Hartikainen
Produced using the clouds, flames and glass blocks plug-ins in Paint.net and the resulting .PNG vectorised with Vector Magic.
Source Firkin
Lovely light gray floral motif with some subtle shades.
Source GraphicsWall
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Could be paper, could be a Polaroid frame – up to you!
Source Chaos
From a drawing in 'Az Osztrák-Magyar Monarchia irásban és képben', 1885.
Source Firkin
The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Remixed from a drawing in 'Line and form", Walter Crane, 1914.
Source Firkin
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
He influenced us all. “Don’t be sad because it’s over. Smile because it happened.”
Source Atle Mo
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
A very dark asfalt pattern based off of a photo taken with my iPhone.
Source Atle Mo
Super subtle indeed, a medium gray pattern with tiny dots in a grid.
Source Designova
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin