A seamless marble-like texture colored in light blue.
Source V. Hartikainen
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić
Prismatic Isometric Cube Wireframe Pattern No Background
Source GDJ
Super dark, crisp and detailed. And a Kill Bill reference.
Source Badhon Ebrahim
A free grid paper background pattern for using on web sites.
Source V. Hartikainen
Just like the black maze, only in light gray. Duh.
Source Peax
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
Prismatic Groovy Concentric Background 2
Source GDJ
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
A series of 5 patterns. That’s what the P stands for, if you didn’t guess it.
Source Dima Shiper
This pattern comes in orange, and it looks as if it is "made of glass".
Source V. Hartikainen
Remixed from a drawing that was uploaded to Pixabay by ractapopulous
Source Firkin
One more sharp little tile for you. Subtle circles this time.
Source Blunia
It was called Navy Blue, but I made it dark. You know, the way I like it.
Source Ethan Hamilton
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin