White circles connecting on a light gray background.
Source Mark Collins
Fix and cc0 to get the tile this is based on.
Source SliverKnight
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Number five from the same submitter, makes my job easy.
Source Dima Shiper
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
A background formed from an image of an old tile on the New York Metropolitan Museum of Art website. To get the base tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A seamless pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Derived from a design in 'Storia del Palazzo Vecchio in Firenze', Aurelio Gotti, 1889.
Source Firkin
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Sort of like the Photoshop transparent background, but better!
Source Alex Parker
This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
It has waves, so make sure you don’t get sea sickness.
Source CoolPatterns
This pattern comes in orange, and it looks as if it is "made of glass".
Source V. Hartikainen
A seamless dark leather-like background texture with diagonal lines that look like stitches.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin