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
Farmer could be some sort of fabric pattern, with a hint of green.
Source Fabian Schultz
This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
Retro Circles Background 4 No Black
Source GDJ
One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
A seamless paper background colored in pale yellow.
Source V. Hartikainen
This is a seamless pattern of regular hexagon which has a honeycomb structure.
Source Yamachem
Love the style on this one, very fresh. Diagonal diamond pattern. Get it?
Source INS
With a name this awesome, how can I go wrong?
Source Nikolay Boltachev
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i
Source Firkin
Sometimes you just need the simplest thing.
Source Fabricio
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
A seamless background colored in pale orange. It has a paper like texture with diagonal grid pattern.
Source V. Hartikainen
Zero CC bark from fur tree tileable texture, photographed and made by me. CC0
Source Sojan Janso
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
Bumps, highlight and shadows – all good things.
Source Badhon Ebrahim
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
A series of 5 patterns. That’s what the P stands for, if you didn’t guess it.
Source Dima Shiper