Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Dark, lines, noise, tactile. You get the drift.
Source Anatoli Nicolae
Retro Circles Background 7 No Black
Source GDJ
Number 3 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
A subtle shadowed checkered pattern. Increase the lightness for even more subtle sexiness.
Source Josh Green
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
Pattern Background, Texture, Photoshop Structure style CC0 texture.
Source Darkmoon1968
Brushed aluminum, in a bright gray version. Lovely 2X as well.
Source Andre Schouten
Zero CC tileable hard cover green book, scanned and made by me. CC0
Source Sojan Janso
The image depicts a seamless pattern of a tortoise in tortoiseshell (hexagon).
Source Yamachem
A seamless pattern formed from a tile made from ornament 22. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Abstract Geometric Background 4 No Black
Source GDJ
A textured orange background pattern with vertical stripes.
Source V. Hartikainen
A pattern derived from part of a fractal rendering in Paint.net.
Source Firkin
You could get a bit dizzy from this one, but it might come in handy.
Source Dertig Media
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
A seamless pattern formed from background pattern 102
Source Firkin