A comeback for you: the popular Escheresque, now in black.
Source Patten
Small gradient crosses inside 45-degree boxes, or bigger crosses if you will.
Source Wassim
A yellow tiled background... Blurriness, bokeh effect and rectangles pattern in one mix.
Source V. Hartikainen
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
To get the tile this is made up from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Zero CC tileable brick texture, photographed and made by me. CC0
Source Sojan Janso
The image depicts a seamless pattern of a Japanese family crest called "chidori" in Japanese .A chidori in Japanese means a plover in English.
Source Yamachem
Scanned some rice paper and tiled it up for you. Enjoy.
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
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin
Dark Tile-able Grunge Texture. I think this texture can be classified as grunge. It's free and seamless, as always.
Source V. Hartikainen
The file was named striped lens, but hey – Translucent Fibres works too.
Source Angelica
From a drawing of the coat of arms of the Ottoman Empire on Wikimedia.
Source Firkin
A seamless pattern of "sewn stripes" colored in light gray.
Source V. Hartikainen
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Tile-able Dark Brown Wood Background. Feel free to use it as a background image in your designs or somewhere on the web. By the way, the color seems to be close to Coffee Brown.
Source V. Hartikainen
Here's a repeatable texture that resembles a light green concrete wall or something similar.
Source V. Hartikainen
Prismatic Curved Diamond Pattern 7 No Background
Source GDJ
High detail stone wall with minor cracks and specks.
Source Projecteightyfive
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin