Snap! It’s a pattern, and it’s not grayscale! Of course you can always change the color in Photoshop.
Source Atle Mo
Seamless tile drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Zero CC tileable cork floor, photographed and made by me. CC0
Source Sojan Janso
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
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
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868
Source Firkin
This was submitted in a beige color, hence the name. Now it’s a gray paper pattern.
Source Konstantin Ivanov
Zero CC tileable brick texture, photographed and made by me. CC0
Source Sojan Janso
Here's a subtle marble-like background for use on websites.
Source V. Hartikainen
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Seamless pattern made from a tile that can be obtained in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Luxurious looking pattern (for a T-shirt maybe?) with a hint of green.
Source Simon Meek
Super simple but very nice indeed. Gray with vertical stripes.
Source Merrin Macleod
Prismatic Abstract Geometric Background 4
Source GDJ
Remixed from a design on Pixabay. To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Prismatic Curved Diamond Pattern 7 No Background
Source GDJ
A classic dark tile for a bit of vintage darkness.
Source Listvetra
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Redrawn based on a drawing in 'По Сѣверо-Западу Россіи' Konstantin Sluchevsky, 1897.
Source Firkin
Very dark pattern with some noise and 45-degree lines.
Source Stefan Aleksić
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin