CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Remixed from a JPG that was uploaded to Pixabay by theasad121
Source Firkin
Sort of reminds me of those old house wallpapers.
Source Tish
A light background pattern with diagonal stripes. Here's a simple light striped background for you.
Source V. Hartikainen
Remixed from a drawing that was uploaded to Pixabay by captenpub.
Source Firkin
Fake or not, it’s quite luxurious.
Source Factorio.us Collective
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.
Source Atle Mo
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prismatic Polka Dots 3 No Background
Source GDJ
A dark pattern made out of 3×3 circles and a 1px shadow. This works well as a carbon texture or background.
Source Atle Mo
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
A seamless pattern formed from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Smooth Polaroid pattern with a light blue tint.
Source Daniel Beaton
A seamless paper background colored in pale yellow.
Source V. Hartikainen
This pack of filters can help you adding a blocky overlay to objects. May come handy at drawing blocks of stone.
Source Lazur URH
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Black version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin