Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
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
A car pattern?! Can it be subtle? I say yes!
Source Radosław Rzepecki
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Bumps, highlight and shadows – all good things.
Source Badhon Ebrahim
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
You may use it as is, or modify it as you like.
Source V. Hartikainen
The image a seamless pattern derived from a weed which I can't identify.The original weed image is from here:https://jp.pinterest.com/pin/500744052301423641/
Source Yamachem
A background pattern with blue on white vertical stripes.
Source V. Hartikainen
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Derived from a drawing in 'The Murmur of the Shells', Samuel Cowen, 1879.
Source Firkin
From a drawing in 'Royal Ramsgate', James Simson, 1897.
Source Firkin
Same classic 45-degree pattern, dark version.
Source Luke McDonald
A black tile-able background with paper-like texture.
Source V. Hartikainen
Prismatic Floral Background No Black
Source GDJ
Lovely pattern with some good-looking non-random noise lines.
Source Zucx
The perfect pattern for all your blogs about type, or type-related matters.
Source Atle Mo
Prismatic Groovy Concentric Background 3
Source GDJ
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Heavily remixed from a drawing in 'Barbara Leybourne; a story of eighty years ago', Sarah Hamer, 1889.
Source Firkin
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin