A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Like the name suggests, this background image consists of a pattern of dark bricks. It may be an option for you, if you are looking for something that looks like a brick wall for use as a background on web pages. It's not a masterpiece, but looks pretty nice when is tiled.
Source V. Hartikainen
A seamless pattern recreated from an image on Pixabay. It is reminiscent of parquet flooring and is formed from a square tile, which can be recovered in Inkscape by selecting the ungrouped rectangle and using shift-alt-I together.
Source Firkin
The texture of this background image has some similarities with leather, and it's colored in a dark brown color. So, if you are looking for a dark brown background image for your website, this may be an option for you.
Source V. Hartikainen
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Derived from an image that was uploaded to Pixabay by darkmoon1968
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
The starting point for this was a texture drawn with the 'Radial Colors' plug-in in Paint.net.
Source Firkin
This is a remix of "geometrical pattern 01".
Source Yamachem
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
The original enhanced with some gradients.
Source Firkin
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
Wild Oliva or Oliva Wilde? Darker than the others, sort of a medium dark pattern.
Source Badhon Ebrahim
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Remixed from a design on Pixabay. To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Continuing the geometric trend, here is one more.
Source Mike Warner
This tiled background comes in red and consists of tiles that look like gemstones. It is more for blogs or social profiles, I think.
Source V. Hartikainen
Prismatic Curved Diamond Pattern 7 No Background
Source GDJ
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
Floral patterns might not be the hottest thing right now, but you never know when you need it!
Source Lauren
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
More leather, and this time it’s bigger! You know, in case you need that.
Source Elemis