A good starting point for a cardboard pattern. This would work well in a variety of colors.
Source Atle Mo
Same as the black version, but now in shades of gray. Very subtle and fine grained.
Source Atle Mo
CC0 remixed from a drawing. Walter Crane, 1914, Firkin.
Source SliverKnight
Tiny, tiny 3D cubes. Reminds me of the good old pattern from k10k.
Source Etienne Rallion
I love the movie Pineapple Express, and I’m also liking this Pineapple right here.
Source Audee Mirza
Light gray paper pattern with small traces of fiber and some dust.
Source Atle Mo
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green
White fabric looking texture with some nice random wave features.
Source Hendrik Lammers
A tile-able background for websites with paper-like texture and a grid pattern layered on top of it.
Source V. Hartikainen
Prismatic Geometric Tessellation Pattern 3 No Background
Source GDJ
Clean and crisp lines all over the place. Wrap it up with this one.
Source Dax Kieran
Prismatic Hypnotic Pattern No Background
Source GDJ
A fun-looking elastoplast/band-aid pattern. A hint of orange tone in this one.
Source Josh Green
Vertical lines with a bumpy, yet crisp, feel to it.
Source Raasa
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
From a drawing in 'Heroes of North African Discovery', Nancy Meugens, 1894.
Source Firkin
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
A background pattern with a look of rough fabric.
Source V. Hartikainen
The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Hexagonal dark 3D pattern. What more can you ask for?
Source Norbert Levajsics