Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Zero CC tileable ground cracked, crackled, texture, made by me.
Source Sojan Janso
Alternative colour scheme. Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
From a drawing in 'La Principauté de Liège et les Pays-Bas au XVIe siècle', Société des Bibliophiles Liégeois ,1887.
Source Firkin
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
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
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
Paper model of a tetrahedron. Modelo de papel de um tetraedro.
Source laobc
A colourful background drawn originally in paint.net and vectorised in Vector Magic.
Source Firkin
Could be paper, could be a Polaroid frame – up to you!
Source Chaos
Prismatic Abstract Background Design
Source GDJ
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
A seamless pattern formed from a square tile based on a jpg on Pixabay. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I.
Source Firkin
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
You know you can’t get enough of these linen-fabric-y patterns.
Source James Basoo
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868
Source Firkin
The image depicts a seamless pattern of Japanese Edo pattern called "kikkou-matsu" or "亀甲松" meaning " tortoiseshell-pinetree".The real pinetree is like this: https://jp.pinterest.com/pin/500744052301065077/
Source Yamachem
Abstract Arbitrary Geometric Background derived from an image on Pixabay.
Source GDJ
An alternative colour scheme to the original seamless pattern.
Source Firkin
I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper