A seamless pattern drawn originally in Paint.net by distorting a slice of background pattern 116 and copying the resulting triangle numerous times.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Prismatic Hypnotic Pattern 2 No Background
Source GDJ
A comeback for you: the popular Escheresque, now in black.
Source Patten
He influenced us all. “Don’t be sad because it’s over. Smile because it happened.”
Source Atle Mo
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
Background formed from the original with an emboss effect.
Source Firkin
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
A nice and simple gray stucco material. Great on its own, or as a base for a new pattern.
Source Bartosz Kaszubowski
Nice little grid. Would work great as a base on top of some other patterns.
Source Arno Gregorian
Awesome name, great pattern. Who does not love space?
Source Nick Batchelor
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
From a drawing in 'Friend or Fortune? The story of a strange year', Robert Overton, 1897.
Source Firkin
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
Seamless Prismatic Quadrilateral Line Art Pattern No Background
Source GDJ
A simple example on using clones. You can generate a nice base for a pattern fill quickly with it.
Source Lazur URH
Prismatic Isometric Cube Wireframe Pattern No Background
Source GDJ
The image depicts a seamless pattern of pine tree leaves.
Source Yamachem
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A beautiful dark wood pattern, superbly tiled.
Source Omar Alvarado
This seamless pattern consists of a blue grid on a yellow background.
Source V. Hartikainen
CC0 remixed from a drawing. Walter Crane, 1914, Firkin.
Source SliverKnight
Based on an image that was uploaded to Pixabay by devanath
Source Firkin
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić