Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
Remixed from a JPG that was uploaded to Pixabay by Osckar
Source Firkin
This one resembles a black concrete wall when is tiled. It should look great, at least with dark website themes.
Source V. Hartikainen
Background Wall, Art Abstract, Blue Well & CC0 texture.
Source Ractapopulous
Prismatic Groovy Concentric Background 4
Source GDJ
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
Dark and hard, just the way we like it. Embossed triangles makes a nice pattern.
Source Ivan Ginev
I have no idea how to describe this one, but it’s light and delicate.
Source JBasoo
Seamless Background For Websites. It has a texture similar to cork-board.
Source V. Hartikainen
The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Prismatic Groovy Concentric Background 2 No Black
Source GDJ
A seamless pattern formed from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
More Japanese-inspired patterns, Gold Scales this time.
Source Josh Green
The tile this is formed from can be retrieved in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
Formed by distorting an image on Pixabay that was uploaded by gustavorezende. To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless pale yellow paper background with a pattern of animal tracks.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Very simple, very blu(e). Subtle and nice.
Source Seb Jachec
Vector version of a png that was uploaded to Pixabay by pencilparker
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
A seamless pattern formed from cross 4. To get the original tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin