From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
This is the remix of "Background pattern 115" uploaded by "Firkin".Thanks.
Source Yamachem
This is lovely, just the right amount of subtle noise, lines and textures.
Source Richard Tabor
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A repeating background with wood/straw like texture.
Source V. Hartikainen
This was submitted in a beige color, hence the name. Now it’s a gray paper pattern.
Source Konstantin Ivanov
You know, tiny and sharp. I’m sure you’ll find a use for it.
Source Atle Mo
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
Prismatic Geometric Pattern Background No Black
Source GDJ
More leather, and this time it’s bigger! You know, in case you need that.
Source Elemis
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Same as gray sand but lighter. A sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
Super dark, crisp and detailed. And a Kill Bill reference.
Source Badhon Ebrahim
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
One more in the line of patterns inspired by Japanese/Asian styles. Smooth.
Source Kim Ruddock
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin