From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A bit like smudged paint or some sort of steel, here is scribble light.
Source Tegan Male
An abstract pale yellow paper-like background with stains colored in yellow and green.
Source V. Hartikainen
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
ZeroCC tileable stone texture, edited from pixabay. CC0
Source Sojan Janso
If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
Love the style on this one, very fresh. Diagonal diamond pattern. Get it?
Source INS
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
Prismatic Abstract Background Design
Source GDJ
Submitted by DomainsInfo – wtf, right? But hey, a free pattern.
Source DomainsInfo
Dead simple but beautiful horizontal line pattern.
Source Fabian Schultz
Paper pattern with small dust particles and 45-degree strokes.
Source Atle Mo
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
The image depicts a seamless pattern of a fishnet with a plenty of fish.It may be a lucky charm for fishermen.
Source Yamachem
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
Dark pattern with some nice diagonal stitched lines crossing over.
Source Ashton
Remixed from a drawing in 'Prehistoric Man: researches into the origin of civilisation in the old and the new world', Daniel Wilson, 1876.
Source Firkin
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
Prismatic Hypnotic Pattern 2 No Background
Source GDJ
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Prismatic Abstract Geometric Background 4
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin