Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.
Source Atle Mo
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
Zero CC tileable pine bark texture, photographed and made by me. CC0
Source Sojan Janso
Your eyes can trip a bit from looking at this – use it wisely.
Source Michal Chovanec
A dark background pattern/texture of a dimpled metal plate.
Source V. Hartikainen
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
Element of beach pattern with background.
Source Rones
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
A comeback for you: the popular Escheresque, now in black.
Source Patten
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
Fake or not, it’s quite luxurious.
Source Factorio.us Collective
Background pattern originally a PNG drawn in Paint.net
Source Firkin
Here I have tried to create something that would look like maple wood. Not sure how well it's turned out, but at least it looks like wood.
Source V. Hartikainen
The image depicts a seamless pattern of a Japanese family crest called "chidori" in Japanese .A chidori in Japanese means a plover in English.
Source Yamachem
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers
Prismatic Abstract Geometric Background 4 No Black
Source GDJ
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
Zero CC plastic pattern texture, photographed and made by me. CC0 *Note, this texture was on the perfectly smooth surface of a plastic shovel scraper, not sure how to call it. Plz coment if you know what its called.
Source Sojan Janso
A simple circle. That’s all it takes. This one is even transparent, for those who like that.
Source Saqib
Paper pattern with small dust particles and 45-degree strokes.
Source Atle Mo
A light gray fabric pattern with faded vertical stripes.
Source V. Hartikainen
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Super dark, crisp and detailed. And a Kill Bill reference.
Source Badhon Ebrahim