This is a seamless pattern of regular hexagon which has a honeycomb structure.
Source Yamachem
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
The tile this is formed from can be retrieved in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A background pattern with wavy green vertical stripes. This one has green stripes on a white background. Download if you like it.
Source V. Hartikainen
Seamless Prismatic Quadrilateral Line Art Pattern No Background
Source GDJ
Because I love dark patterns, here is Brushed Alum in a dark coating.
Source Tim Ward
All good things come in threes, so I give you the third in my little concrete wall series.
Source Atle Mo
Greyscale version of a pattern that came out of playing with the 'slinky' plug-in for Paint.net
Source Firkin
Prismatic Snowflakes Pattern No Background
Source GDJ
This is so subtle you need to bring your magnifier!
Source Carlos Valdez
Abstract Stars Geometric Pattern Prismatic No Background
Source GDJ
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.
Source Firkin
Three shades of gray makes this pattern look like a small carbon fiber surface. Great readability even for small fonts.
Source Atle Mo
This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley
Not even 1kb, but very stylish. Gray thin lines.
Source Struck Axiom
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin