This pattern comes in orange, and it looks as if it is "made of glass".
Source V. Hartikainen
A repeatable image with dark background and metal grid pattern.
Source V. Hartikainen
From an image on opengameart.org shared by rubberduck.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.
Source Firkin
From a drawing in 'Hundert Jahre in Wort und Bild', S. Stefan, 1899.
Source Firkin
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
Colorful Floral Background 3 No Black
Source GDJ
This was formed by distorting an image of a background on Pixabay.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Colour version of the original pattern inspired by the front cover of 'Old and New Paris', Henry Edwards, 1894.
Source Firkin
A free tileable background colored in off-white (antique white) color.
Source V. Hartikainen
The image a seamless pattern of a wire-mesh fence.I want you to use this pattern as a lower layer.
Source Yamachem
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
Seamless Prismatic Pythagorean Line Art Pattern No Background. A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
A dark metal plate with an embossed grid pattern and a bit of rust. Here's a dark metal plate texture for use as a tiled background on web pages.
Source V. Hartikainen
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Nasty or not, it’s a nice pattern that tiles. Like they all do.
Source Badhon Ebrahim
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
Submitted by DomainsInfo – wtf, right? But hey, a free pattern.
Source DomainsInfo
Just like the black maze, only in light gray. Duh.
Source Peax
Remixed from a drawing that was uploaded to Pixabay by DavidZydd
Source Firkin
Remixed from a JPG that was uploaded to Pixabay by theasad121
Source Firkin