A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
Prismatic Triangular Background Design Mark II 5
Source GDJ
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
Light honeycomb pattern made up of the classic hexagon shape.
Source Federica Pelzel
Utilising a bird from s-light and some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
A seamless web background with texture of aged grid paper.
Source V. Hartikainen
Prismatic Geometric Pattern Background
Source GDJ
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
Thin lines, noise and texture creates this crisp dark denim pattern.
Source Marco Slooten
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i
Source Firkin
Abstract Tiled Background Extended 6
Source GDJ
A seamless pattern the starting point for which was a 'light rays' rendering in Paint.net.
Source Firkin
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
The Grid. A digital frontier. I tried to picture clusters of information as they traveled through the computer.
Source Haris Šumić
A large pattern with funky shapes and form. An original. Sort of origami-ish.
Source Luuk van Baars
Formed by heavily distorting part of a an image of a fish uploaded to Pixabay by GLady
Source Firkin
Prismatic Groovy Concentric Background 5 No Black
Source GDJ