The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
These dots are already worn for you, so you don’t have to.
Source Matt McDaniel
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Prismatic Geometric Pattern Background
Source GDJ
A chequerboard pattern with a fruit theme. The fruits are from a posting by inkscapeforum.it.
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
Based on an image that was uploaded to Pixabay by devanath
Source Firkin
Tiny circle waves, almost like the ocean.
Source Sagive
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857
Source Firkin
The classic 45-degree diagonal line pattern, done right.
Source Jorick van Hees
Tiny, tiny 3D cubes. Reminds me of the good old pattern from k10k.
Source Etienne Rallion
Derived from an image that was uploaded to Pixabay by TheDigitalArtist
Source Firkin
A simple but elegant classic. Every collection needs one of these.
Source Christopher Burton
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
This one needs to be used in small areas; you can see it repeat.
Source Luca
Prismatic Groovy Concentric Background 3
Source GDJ
Remixed from a drawing that was uploaded to Pixabay by captenpub.
Source Firkin
Luxurious looking pattern (for a T-shirt maybe?) with a hint of green.
Source Simon Meek
This is the remix of "blue wave-seigaiha".This is the flowers of pink silk tree which is called "nemuno-ki".About pink silk tree ,refer to here:https://jp.pinterest.com/pin/500744052301210439/
Source Yamachem
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin