Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.
Source Atle Mo
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Sharp pixel pattern, just like the good old days.
Source Paridhi
Pattern Background, Texture, Photoshop Structure style CC0 texture.
Source Darkmoon1968
Turn your site into a dragon with this great scale pattern.
Source Alex Parker
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
A pale orange background pattern with glossy groove stripes.
Source V. Hartikainen
Background pattern made in "Grunge-Like" style. Available in both SVG and JPG formats. Edit to your needs then click the download button.
Source V. Hartikainen
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Sharp pixel pattern, just like the good old days.
Source Paridhi
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
Remixed from a vector adapted from a jpg on Pixabay. The tile this is constructed from can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Did anyone say The Hoff? This pattern is in no way related to Baywatch.
Source Josh Green
ZeroCC tileable beechwood wood texture, generated in Neo Texture Edit by me. CC0
Source Sojan Janso
Derived from a drawing in 'The Murmur of the Shells', Samuel Cowen, 1879.
Source Firkin
Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
Because I love dark patterns, here is Brushed Alum in a dark coating.
Source Tim Ward