CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
The image depicts a seamless pattern made using a bird's face.
Source Yamachem
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A pale yellow background pattern with vertical stripes. The stripes are partially faded. I think this background image turned out pretty well, especially those faded stripes.
Source V. Hartikainen
Prismatic Basic Pattern 2 No Background
Source GDJ
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
The image is a seamless pattern of a fishnet.
Source Yamachem
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
Background formed from the original with an emboss effect.
Source Firkin
Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
Coming in at 666x666px, this is an evil big pattern, but nice and soft at the same time.
Source Atle Mo
Prismatic Abstract Geometric Background derived from an image on Pixabay.
Source GDJ
Retro Circles Background 4 No Black
Source GDJ
From a drawing in 'Royal Ramsgate', James Simson, 1897.
Source Firkin
Tweed is back in style – you heard it here first. Also, the @2X version here is great!
Source Simon Leo
Hey, you never know when you’ll need a bird pattern, right?
Source Pete Fecteau