A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
The image depicts a seamless pattern which was made using stripe-like things including borders.I used OCAL cliparts called "Blue Greek Key With Lines Border" uploaded by "GR8DAN" and "daisy border" uploaded by "johnny_automatic".Thanks.
Source Yamachem
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
The following repeating website background is colored in a blue gray color and resembles a concrete wall or something similar to it.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Prismatic Polka Dots Mark II 2 No Background
Source GDJ
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
An abstract Background pattern of purple twisty patterns.
Source TikiGiki
A seamless pattern of dark bricks. Maybe it's not very realistic, but it looks good in my opinion.
Source V. Hartikainen
Hexagonal dark 3D pattern. What more can you ask for?
Source Norbert Levajsics
Prismatic Groovy Concentric Background 3
Source GDJ
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
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
From a drawing in 'Kingsdene', Maria Fetherstonehaugh, 1878.
Source Firkin
Awesome name, great pattern. Who does not love space?
Source Nick Batchelor
Prismatic Abstract Line Art Pattern Background 2
Source GDJ
A light gray wall or floor (you decide) of concrete.
Source Atle Mo
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin