This is sort of fresh, but still feels a bit old school.
Source Martuchox
Prismatic Hypnotic Pattern 2 No Background
Source GDJ
Remixed from a drawing in 'Analecta Eboracensia', Thomas Widdrington, 1897.
Source Firkin
First pattern tailor-made for Retina, with many more to come. All the old ones are upscaled, in case you want to re-download.
Source Atle Mo
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
Prismatic Groovy Concentric Background 3 No Black
Source GDJ
A repeating background with wood/straw like texture.
Source V. Hartikainen
Here's a new paper-like background for free use on personal and commercial projects (this applies to all background patterns here).
Source V. Hartikainen
A seamless pattern with a unit cell drawn as a bitmap in Paint.net and vectorized in Vector Magic.
Source Firkin
It was called Navy Blue, but I made it dark. You know, the way I like it.
Source Ethan Hamilton
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Here's a seamless brown cork board background texture. Feel free to download or reshare if you like.
Source V. Hartikainen
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Sharp pixel pattern, just like the good old days.
Source Paridhi
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Number 4 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
Seamless Green Tile Background
Source V. Hartikainen
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin