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
Prismatic Isometric Cube Wireframe Pattern No Background
Source GDJ
The classic 45-degree diagonal line pattern, done right.
Source Jorick van Hees
A brown seamless wood texture in a form of stripe pattern. The result has turned out pretty well, in my opinion.
Source V. Hartikainen
This metal background pattern resembles a metal plate with rivets. Solid rivets on a metal plate.
Source V. Hartikainen
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prismatic Snowflakes Pattern 2 No Background
Source GDJ
Remixed from a drawing that was uploaded to Pixabay by DavidZydd
Source Firkin
A seamless pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
More tactile goodness. This time in the form of some rough cloth.
Source Bartosz Kaszubowski
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
ZeroCC tileable stone texture, edited from pixabay. CC0
Source Sojan Janso
A pale orange background pattern with glossy groove stripes.
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Everyone loves a diamond, right? Make your site sparkle.
Source AJ Troxell