I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
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
This light background pattern has a texture of "frozen" surface with diagonal stripes. Here's an yet another addition to the collection of free website backgrounds.
Source V. Hartikainen
This is indeed a bit strange, but here’s to the crazy ones!
Source Christopher Buecheler
Bit of a strange name on this one, but still nice. Tiny gray square things.
Source Carlos Valdez
Prismatic Floral Background No Black
Source GDJ
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Dead simple but beautiful horizontal line pattern.
Source Fabian Schultz
Basket Fibers, Basket Texture, Braid Background style CC0 texture.
Source 1A-Photoshop
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
Nice little grid. Would work great as a base on top of some other patterns.
Source Arno Gregorian
This is a hot one. Small, sharp and unique.
Source GraphicsWall
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
Lovely light gray floral motif with some subtle shades.
Source GraphicsWall
Luxurious looking pattern (for a T-shirt maybe?) with a hint of green.
Source Simon Meek
A dark metallic background with a pattern of stamped dots. Here's a dark "metallic" background pattern for you.
Source V. Hartikainen
Number 4 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
A version without colours blended together to give a different look.
Source Firkin
A simple example on using clones. You can generate a nice base for a pattern fill quickly with it.
Source Lazur URH
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
From a drawing in 'Kingsdene', Maria Fetherstonehaugh, 1878.
Source Firkin
The tile can be had by using shift+alt+i on the selected rectangle in Inkscape
Source Firkin