This could be a hippy vintage wallpaper.
Source Tileable Patterns
The tile for this is based on a repeating unit close to a design on Pixabay. It can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Zero CC tileable Crackled Cement (streaks) texture, photographed and made by me. CC0
Source Sojan Janso
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
That’s what it is, a dark dot. Or sort of carbon looking.
Source Tsvetelin Nikolov
On a large canvas you can see it tiling, but used on smaller areas, it’s beautiful.
Source Paul Phönixweiß
Remixed from a drawing in 'Analecta Eboracensia', Thomas Widdrington, 1897.
Source Firkin
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
An alternative colour scheme to the original seamless pattern.
Source Firkin
The name tells you it has curves. Oh yes, it does!
Source Peter Chon
A seamless pattern formed from a sports car on clker.com. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A version without colours blended together to give a different look.
Source Firkin
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
Medium gray pattern with small strokes to give a weave effect.
Source Catherine
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Pattern produced in Paint.net using the Vibrato plug-in.
Source Firkin
This is a hot one. Small, sharp and unique.
Source GraphicsWall
Little x’es, noise and all the stuff you like. Dark like a Monday, with a hint of blue.
Source Tom McArdle
That’s what it is, a dark dot. Or sort of carbon looking.
Source Tsvetelin Nikolov
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin