This is a seamless pattern of regular hexagon which has a honeycomb structure.
Source Yamachem
This makes me wanna shoot some pool! Sweet green pool table pattern.
Source Caveman
A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
A light gray wall or floor (you decide) of concrete.
Source Atle Mo
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
This one is amazing, truly original. Go use it!
Source Viahorizon
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Derived from a PNG that was uploaded to Pixabay by nutkitten
Source Firkin
A dark pattern made out of 3×3 circles and a 1px shadow. This works well as a carbon texture or background.
Source Atle Mo
Same as Silver Scales, but in black. Turn your site into a dragon with this great scale pattern.
Source Alex Parker
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Sort of like the back of a wooden board. Light, subtle, and stylish, just the way we like it!
Source Nikolalek
Real snow that tiles, not easy. This is not perfect, but an attempt.
Source Atle Mo
This beige background pattern resembles a concrete wall with engravings or something similar to it.
Source V. Hartikainen
Psychedelic Geometric Background No Black
Source GDJ
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Number five from the same submitter, makes my job easy.
Source Dima Shiper
Remixed from a drawing in 'Line and form", Walter Crane, 1914.
Source Firkin