From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
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
Same as the black version, but now in shades of gray. Very subtle and fine grained.
Source Atle Mo
Colour version of the original pattern inspired by the front cover of 'Old and New Paris', Henry Edwards, 1894.
Source Firkin
Light honeycomb pattern made up of the classic hexagon shape.
Source Federica Pelzel
The image depicts a seamless pattern of a Japanese family crest called "chidori" in Japanese .A chidori in Japanese means a plover in English.
Source Yamachem
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Sweet and subtle white plaster with hints of noise and grunge.
Source Phil Maurer
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective