CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
Remixed from a raster on Pixabay, that was uploaded by ArtsyBee.
Source Firkin
Prismatic Groovy Concentric Background 5
Source GDJ
More carbon fiber for your collections. This time in white or semi-dark gray.
Source Badhon Ebrahim
Colorful Floral Background 3 No Black
Source GDJ
Abstract Tiled Background Extended 12
Source GDJ
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Polka Dots Mark II No Background
Source GDJ
Same classic 45-degree pattern, dark version.
Source Luke McDonald
You know you can’t get enough of these linen-fabric-y patterns.
Source James Basoo
Prismatic Curved Diamond Pattern 7 No Background
Source GDJ
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
Could remind you a bit of those squares in Super Mario Bros, yeh?
Source Jeff Wall
From a drawing of the coat of arms of the Ottoman Empire on Wikimedia.
Source Firkin
A seamless pattern formed from a modified version of rwwgub's tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
A bit of scratched up grayness. Always good.
Source Dmitry
Inspired by a drawing in 'Kulturgeschichte', Freidrich Hellwald, 1896.
Source Firkin
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
A slightly grainy paper pattern with small horizontal and vertical strokes.
Source Atle Mo
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin