The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
Black And White Floral Pattern Background Inverse
Source GDJ
Alternative colour scheme for the original floral pattern.
Source Firkin
Remixed from a drawing in 'The March of Loyalty', Letitia MacClintock, 1884.
Source Firkin
These dots are already worn for you, so you don’t have to.
Source Matt McDaniel
Small gradient crosses inside 45-degree boxes, or bigger crosses if you will.
Source Wassim
The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Abstract Stars Geometric Pattern Prismatic No Background
Source GDJ
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
A free background image with a seamless texture of cardboard. This texture of cardboard looks quite realistic, especially when is actually tiled.
Source V. Hartikainen
Clean and crisp lines all over the place. Wrap it up with this one.
Source Dax Kieran
A dark background pattern/texture of a dimpled metal plate.
Source V. Hartikainen
Super dark, crisp and detailed. And a Kill Bill reference.
Source Badhon Ebrahim
From a drawing in 'Heroes of North African Discovery', Nancy Meugens, 1894.
Source Firkin
A background pattern with blue on white vertical stripes.
Source V. Hartikainen
A yellow tiled background... Blurriness, bokeh effect and rectangles pattern in one mix.
Source V. Hartikainen
A seamless light gray paper texture with horizontal double lines.
Source V. Hartikainen
Dark, crisp and subtle. Tiny black lines on top of some noise.
Source Wilmotte Bastien
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
I’m starting to think I have a concrete wall fetish.
Source Atle Mo
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
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
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I. Version with black background.
Source Firkin
Prismatic Groovy Concentric Background 5
Source GDJ