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
New paper pattern with a slightly organic feel to it, using some thin threads.
Source Atle Mo
Prismatic Abstract Geometric Background 4
Source GDJ
It’s okay to be square! A nice light gray pattern with random squares.
Source Waseem Dahman
Continuing the geometric trend, here is one more.
Source Mike Warner
Prismatic Abstract Line Art Pattern Background
Source GDJ
This is the remix of "polka dot seamless pattern".The image depicts polka dot seamless pattern.
Source Yamachem
A seamless pattern of "sewn stripes" colored in light gray.
Source V. Hartikainen
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin
Prismatic Groovy Concentric Background 3
Source GDJ
A pale olive green background with a seamless texture.
Source V. Hartikainen
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
Medium gray pattern with small strokes to give a weave effect.
Source Catherine
Smooth Polaroid pattern with a light blue tint.
Source Daniel Beaton
With a name this awesome, how can I go wrong?
Source Nikolay Boltachev
Prismatic Triangular Background Design Mark II 5
Source GDJ
Paper pattern with small dust particles and 45-degree strokes.
Source Atle Mo
Derived from an image that was uploaded to Pixabay by mdmelo.
Source Firkin
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Sounds French. Some 3D square diagonals, that’s all you need to know.
Source Graphiste