Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
ZeroCC tileable beechwood wood texture, generated in Neo Texture Edit by me. CC0
Source Sojan Janso
Prismatic Abstract Line Art Pattern Background
Source GDJ
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
A seamless pattern the unit cell for which 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
An attempt for cleaning up the original image in a few steps.
Source Lazur URH
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green
You just can’t get enough of the fabric patterns, so here is one more for your collection.
Source Krisp Designs
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
Greyscale version of a pattern that came out of playing with the 'slinky' plug-in for Paint.net
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i
Source Firkin
Remixed from an image that was uploaded to Pixabay by Pixeline
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Remixed from a raster on Pixabay that was uploaded by ArtsyBee.
Source Firkin
I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin