Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Zero CC tileable pine bark texture, photographed and made by me. CC0
Source Sojan Janso
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
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
This was formed by distorting an image of a background on Pixabay.
Source Firkin
White little knobs, coming in at 10x10px. Sweet!
Source Amos
Looks as if it's spray painted on the wall. You can be sure that this pattern will seamlessly fill your backgrounds on web pages.
Source V. Hartikainen
I scanned a paper coffee cup. You know, in case you need it.
Source Atle Mo
Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
Prismatic Abstract Background Design
Source GDJ
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prismatic Triangular Background Design Mark II 5
Source GDJ
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Inspired by a pattern seen on a public domain image of a very old tile. To get the unit cell, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
Prismatic Groovy Concentric Background 2 No Black
Source GDJ
A seamless pattern the starting point for which was a 'light rays' rendering in Paint.net.
Source Firkin