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
Can’t believe we don’t have this in the collection already! Slick woven pattern with crisp details.
Source Max Rudberg
It’s like Shine Dotted’s sister, only rotated 45 degrees.
Source mediumidee
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
Has nothing to do with toast, but it’s nice and subtle.
Source Pippin Lee
Vertical lines with a bumpy, yet crisp, feel to it.
Source Raasa
A very dark spotted twinkle pattern for your twinkle needs.
Source Badhon Ebrahim
A car pattern?! Can it be subtle? I say yes!
Source Radosław Rzepecki
White fabric looking texture with some nice random wave features.
Source Hendrik Lammers
Continuing the geometric trend, here is one more.
Source Mike Warner
Number 3 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
Remixed from a raster on Pixabay that was uploaded by ArtsyBee.
Source Firkin
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
A free grid paper background pattern for using on web sites.
Source V. Hartikainen
Neat little photography icon pattern.
Source Hossam Elbialy
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
Remixed from a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
This metal background pattern resembles a metal plate with rivets. Solid rivets on a metal plate.
Source V. Hartikainen