A comeback for you: the popular Escheresque, now in black.
Source Patten
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i
Source Firkin
Here's an yet another background for websites, with a seamless texture of wood planks this time.
Source V. Hartikainen
A seamless pattern the starting point for which was a 'light rays' rendering in Paint.net.
Source Firkin
Pixel by pixel, sharp and clean. Very light pattern with clear lines.
Source M.Ashok
Abstract Tiled Background Extended 6
Source GDJ
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Black And White Floral Pattern Background from PDP.
Source GDJ
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
Zero CC tileable grass texture, photographed and made by me. CC0
Source Sojan Janso
Light gray pattern with an almost wall tile-like appearance.
Source Markus Tinner
The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Clean and crisp lines all over the place. Wrap it up with this one.
Source Dax Kieran
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
A pattern drawn in Paint.net and vectorized in Inkscape.
Source Firkin
Used correctly, this could be nice. Used in a bad way, all hell will break loose.
Source Atle Mo
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
I’m not going to use the word Retina for all the new patterns, but it just felt right for this one. Huge wood pattern for ya’ll.
Source Atle Mo
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
Prismatic Curved Diamond Pattern 8 No Background
Source GDJ
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Prismatic Groovy Concentric Background No Black
Source GDJ