Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
Prismatic Triangular Background Design Mark II 5
Source GDJ
Prismatic Polka Dots 3 No Background
Source GDJ
Dark and hard, just the way we like it. Embossed triangles makes a nice pattern.
Source Ivan Ginev
Prismatic Geometric Pattern Background
Source GDJ
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
A dark pattern made out of 3×3 circles and a 1px shadow. This works well as a carbon texture or background.
Source Atle Mo
The image depicts an edo-era pattern called "same-komon" or "鮫小紋"which looks like a shark skin.The "same" in Japanese means shark in English.
Source Yamachem
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Remixed from an image on Pixabay uploaded by Prawny
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
The tile this is formed from can be retrieved in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
A seamless pattern drawn originally in Paint.net by distorting a slice of background pattern 116 and copying the resulting triangle numerous times.
Source Firkin
Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
Derived from a drawing in 'The Murmur of the Shells', Samuel Cowen, 1879.
Source Firkin
Colour version that is close to the original drawing uploaded to Pixabay by pencilparker.
Source Firkin
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
Stefan is hard at work, this time with a funky pattern of squares.
Source Stefan Aleksić
Prismatic Abstract Line Art Pattern Background
Source GDJ
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
The classic 45-degree diagonal line pattern, done right.
Source Jorick van Hees
Prismatic Curved Diamond Pattern 8 No Background
Source GDJ