This is so subtle you need to bring your magnifier!
Source Carlos Valdez
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Tiny, tiny 3D cubes. Reminds me of the good old pattern from k10k.
Source Etienne Rallion
Everyone needs some stardust. Sprinkle it on your next project.
Source Atle Mo
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
A nice and simple white rotated tile pattern.
Source Another One
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
Pattern produced in Paint.net using the Vibrato plug-in.
Source Firkin
This pack of filters can help you adding a blocky overlay to objects. May come handy at drawing blocks of stone.
Source Lazur URH
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
Remixed from a JPG that was uploaded to Pixabay by theasad121
Source Firkin
Dark, crisp and subtle. Tiny black lines on top of some noise.
Source Wilmotte Bastien
Retro Circles Background 7 No Black
Source GDJ
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
A seamless pattern with wide vertical stripes colored in pale yellow.
Source V. Hartikainen
Nicely crafted paper pattern, although a bit on the large side (500x593px).
Source Blaq Annabiosis
The classic 45-degree diagonal line pattern, done right.
Source Jorick van Hees
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
A seamless pattern created from a square tile. To get the tile, select the pattern in Inkscape and use shift+alt+i.
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