This is indeed a bit strange, but here’s to the crazy ones!
Source Christopher Buecheler
Dark, lines, noise, tactile. You get the drift.
Source Anatoli Nicolae
Based on an image that was uploaded to Pixabay by devanath
Source Firkin
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Orange-red pattern for tiled backgrounds.
Source V. Hartikainen
Inspired by a drawing in 'Poems', James Smith, 1881.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
It’s big, it’s gradient—and it’s square.
Source Brankic1979
By popular request, an outline version of the pentagon pattern.
Source Atle Mo
The starting point for this was a texture drawn with the 'Radial Colors' plug-in in Paint.net.
Source Firkin
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use 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
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
Prismatic Geometric Pattern Background
Source GDJ
A dark gray, sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
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
8 by 8 pixels, and just what the title says.
Source pixilated
A seamless background pattern with a texture of wood planks. This wood background pattern has vertically arranged planks. You may try to rotate it 90°, to see how it will look like when the wood planks are arranged horizontally.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Thin lines, noise and texture creates this crisp dark denim pattern.
Source Marco Slooten
I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper