From a drawing in 'Two Women in the Klondike', Mary Hitchcock, 1899.
Source Firkin
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
Same as gray sand but lighter. A sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
I love cream! 50x50px and lovely in all the good ways.
Source Thomas Myrman
U.S.-based National Fire Protection Association standard fire diamond for flagging risks posed by hazardous materials. The red diamond has a number 0-4 depending on flammability. The blue diamond has a number 0-4 depending on health hazard. The yellow has a number 0-4 depending on reactivity. the white square has a special notice, e.g OX for oxidizer.
Source Firkin
Not even 1kb, but very stylish. Gray thin lines.
Source Struck Axiom
This was submitted in a beige color, hence the name. Now it’s a gray paper pattern.
Source Konstantin Ivanov
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
From a drawing in 'A Life Interest', Mrs Alexander, 1888.
Source Firkin
You know you can’t get enough of these linen-fabric-y patterns.
Source James Basoo
Derived from an image that was uploaded to Pixabay by mdmelo.
Source Firkin
People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A seamless background pattern with impressed gray dots.
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
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
Abstract Ellipses Background Grayscale
Source GDJ