Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
A nice and simple white rotated tile pattern.
Source Another One
Prismatic Curved Diamond Pattern 6 No Background
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Fix side and a seamless pattern formed from circles.
Source SliverKnight
Prismatic Groovy Concentric Background 3
Source GDJ
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
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
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 grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Inspired by a pattern I saw in a 19th century book. This seamless pattern was created from a square tile. To get the tile, select the pattern in Inkscape and use shift+alt+i.
Source Firkin
A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.
Source Atle Mo
Classic 45-degree pattern, light version.
Source Luke McDonald
Could remind you a bit of those squares in Super Mario Bros, yeh?
Source Jeff Wall
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
Remixed from a PNG that was uploaded to Pixabay by VictorianLady
Source Firkin
A bit like some carbon, or knitted netting if you will.
Source Anna Litvinuk