A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prismatic Abstract Geometric Background 4
Source GDJ
It’s like Shine Dotted’s sister, only rotated 45 degrees.
Source mediumidee
A chequerboard pattern with a fruit theme. The fruits are from a posting by inkscapeforum.it.
Source Firkin
It’s big, it’s gradient—and it’s square.
Source Brankic1979
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Nasty or not, it’s a nice pattern that tiles. Like they all do.
Source Badhon Ebrahim
Square design drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
Derived from a drawing in 'Historiske Afhandlinger', Adolf Jorgensen, 1898.
Source Firkin
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Prismatic Snowflakes Pattern 2 No Background
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Bit of a strange name on this one, but still nice. Tiny gray square things.
Source Carlos Valdez
The tile for this is based on a repeating unit close to a design on Pixabay. It can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Remixed from a drawing that was uploaded to Pixabay by captenpub.
Source Firkin
Dark blue concrete wall with some small dust spots.
Source Atle Mo
Adapted from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin