I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
Prismatic Geometric Pattern Background No Black
Source GDJ
A bit like smudged paint or some sort of steel, here is scribble light.
Source Tegan Male
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
Prismatic Triangular Seamless Pattern III With Background
Source GDJ
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
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
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Background formed from the iconic plastic construction bricks that gave me endless hours of fun when I was a lad.
Source Firkin
Remixed from a drawing in 'Jezebel's Daughter', Wilkie Collins 1880
Source Firkin
Carbon fiber is never out of fashion, so here is one more style for you.
Source Alfred Lee
Light gray pattern with an almost wall tile-like appearance.
Source Markus Tinner
Prismatic Curved Diamond Pattern 2 No Background
Source GDJ
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
More carbon fiber for your collections. This time in white or semi-dark gray.
Source Badhon Ebrahim
A very dark spotted twinkle pattern for your twinkle needs.
Source Badhon Ebrahim
Sharp diamond pattern. A small 24x18px tile.
Source Tom Neal
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
This one has rusty dark brown texture.
Source V. Hartikainen
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
Dark, crisp and subtle. Tiny black lines on top of some noise.
Source Wilmotte Bastien
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
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Here's a brown background pattern with subtle stripes. I hope you'll like the color. If not, feel free to change it using an image editor, if you know how of course. Personally, I'm using GIMP to create these backgrounds.
Source V. Hartikainen
Same as gray sand but lighter. A sandy pattern with small light dots, and some angled strokes.
Source Atle Mo