From a drawing in 'Bond Slaves. The story of a struggle.', Isabella Varley, 1893.
Source Firkin
Prismatic Rounded Squares Grid 4 No Background
Source GDJ
This is sort of fresh, but still feels a bit old school.
Source Martuchox
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Seamless pattern formed from a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
A free green background pattern with a pattern of rhombuses on a seamless texture. Feel free to use it as a tiled background image on your web site.
Source V. Hartikainen
Prismatic Geometric Pattern Background No Black
Source GDJ
Prismatic Basic Pattern 2 No Background
Source GDJ
Retro Circles Background 5 No Black
Source GDJ
Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
You may use it as is, or modify it as you like.
Source V. Hartikainen
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
The starting point for this was drawn on the web site steamcoded.org/PolyskelionMaker.svg
Source Firkin
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
A background pattern with wavy green vertical stripes. This one has green stripes on a white background. Download if you like it.
Source V. Hartikainen
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
Zero CC tileable grass texture, photographed and made by me. CC0
Source Sojan Janso
Abstract Ellipses Background Grayscale
Source GDJ
From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.
Source Firkin
A large pattern with funky shapes and form. An original. Sort of origami-ish.
Source Luuk van Baars