Prepared mostly as a raster in Paint.net and vectorised.
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
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
Not the most creative name, but it’s a good all-purpose light background.
Source Dmitry
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin
A seamless pattern the starting point for which was a 'light rays' rendering in Paint.net.
Source Firkin
From an image on opengameart.org shared by rubberduck.
Source Firkin
A seamless pattern based on a rectangular tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Here's an yet another seamless note paper texture for use as a background on websites.
Source V. Hartikainen
A pattern formed from a photograph of a 16th century ceramic tile.
Source Firkin
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
Prismatic Hexagonalist Pattern No Background
Source GDJ
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
A pale olive green background with a seamless texture.
Source V. Hartikainen
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
Same as Silver Scales, but in black. Turn your site into a dragon with this great scale pattern.
Source Alex Parker
Formed from decorative divider 184 in paint.net. Vectorised with Vector Magic.
Source Firkin
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
This is a seamless pattern which is derived from a flower petal image.
Source Yamachem
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
The name is totally random, but hey, it sounds good.
Source Atle Mo
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Colour version of the original pattern.
Source Firkin
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk