Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
Psychedelic Geometric Background No Black
Source GDJ
More in the paper realm, this time with fibers.
Source Jorge Fuentes
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868
Source Firkin
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Could remind you a bit of those squares in Super Mario Bros, yeh?
Source Jeff Wall
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
We have some linen patterns here, but none that are stressed. Until now.
Source Jordan Pittman
Prismatic Abstract Line Art Pattern Background 2
Source GDJ
Number 4 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
A seamless web texture of "green stone".
Source V. Hartikainen
Number 3 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Dead simple but beautiful horizontal line pattern.
Source Fabian Schultz
A light brushed aluminum pattern for your pleasure.
Source Tim Ward
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
Farmer could be some sort of fabric pattern, with a hint of green.
Source Fabian Schultz
Derived from an image that was uploaded to Pixabay by Kaz
Source Firkin
Prismatic Hypnotic Pattern 2 No Background
Source GDJ
A seamless pattern the starting point for which was a 'colour modulo' texture in Paint.net.
Source Firkin