Seamless pattern formed from a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Prismatic Floral Pattern 3 Variation 3 No Background
Source GDJ
A free background pattern with abstract green tiles.
Source V. Hartikainen
People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
Light gray pattern with an almost wall tile-like appearance.
Source Markus Tinner
Pattern formed from simple shapes. Black version.
Source Firkin
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
Prismatic Curved Diamond Pattern 6 No Background
Source GDJ
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
Background Wall, Art Abstract, Star Well & CC0 texture.
Source Ractapopulous
This light yellow background pattern consists of an irregular pattern of spots. Here's a light background pattern with yellowish tint.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
A set of paper filters. The base texture is generated the same way, only the compositing mode is varied.
Source Lazur URH
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
Inspired by a design found in 'Konstantinápolyi emlékeim', Miklos Chriszto, 1893.
Source Firkin
Abstract Tiled Background Extended 6
Source GDJ
He influenced us all. “Don’t be sad because it’s over. Smile because it happened.”
Source Atle Mo
One more sharp little tile for you. Subtle circles this time.
Source Blunia
Remixed from a drawing in 'Kulturgeschichte der Deutschen im Mittelalter' Franz von Loeher, 1891. The unit tile can be had by selecting the rectangle in Inkscape and using shift-alt-i
Source Firkin
Retro Circles Background 7 No Black
Source GDJ
A pattern formed from repeated instances of corner decoration 8. To get the basic tile select the rectangle in Inkscape and use shift+alt+i
Source Firkin