This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
Colorful Floral Background 3 No Black
Source GDJ
Prismatic Hexagonalism Pattern No Background
Source GDJ
Greyscale version of a pattern that came out of playing with the 'slinky' plug-in for Paint.net
Source Firkin
Prismatic Groovy Concentric Background 2
Source GDJ
Black & white version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
A version without colours blended together to give a different look.
Source Firkin
Seamless Prismatic Pythagorean Line Art Pattern No Background. A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
The image depicts a seamless pattern of Japanese Edo pattern called "kikkou-matsu" or "亀甲松" meaning " tortoiseshell-pinetree".The real pinetree is like this: https://jp.pinterest.com/pin/500744052301065077/
Source Yamachem
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A very dark asfalt pattern based off of a photo taken with my iPhone.
Source Atle Mo
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
A repeating background for websites with a texture of black groove stripes.
Source V. Hartikainen
Another fairly simple design drawn in Paint.net and vectorized in Inkscape.
Source Firkin
Prismatic Geometric Pattern Background No Black
Source GDJ
Super subtle indeed, a medium gray pattern with tiny dots in a grid.
Source Designova
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
Alternative colour scheme. 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
You guessed it – looks a bit like cloth.
Source Peax Webdesign
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin