Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
You know I’m a sucker for these. Well-crafted paper pattern.
Source Mihaela Hinayon
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Prismatic Polka Dots Mark II 2 No Background
Source GDJ
From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.
Source Firkin
Wild Oliva or Oliva Wilde? Darker than the others, sort of a medium dark pattern.
Source Badhon Ebrahim
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Prismatic Curved Diamond Pattern 2 No Background
Source GDJ
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
Dark, crisp and subtle. Tiny black lines on top of some noise.
Source Wilmotte Bastien
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
Remixed from a raster on Pixabay that was uploaded by ArtsyBee.
Source Firkin
Here's a quite bright pink background pattern for use on websites. It doesn't look like a real fur, but it definitely resembles one.
Source V. Hartikainen
Prismatic Groovy Concentric Background 4
Source GDJ
Lovely pattern with splattered vintage speckles.
Source David Pomfret
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
Formed from decorative divider 184 in paint.net. Vectorised with Vector Magic.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Did anyone say The Hoff? This pattern is in no way related to Baywatch.
Source Josh Green
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin