A series of 5 patterns. That’s what the P stands for, if you didn’t guess it.
Source Dima Shiper
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A pattern formed from a photograph of a 16th century ceramic tile.
Source Firkin
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Derived from a PNG that was uploaded to Pixabay by nutkitten
Source Firkin
A seamless pattern the starting point for which was a 'colour modulo' texture in Paint.net.
Source Firkin
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
This ladies and gentlemen, is texturetastic! Love it.
Source Adam Pickering
This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green
I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
One more in the line of patterns inspired by Japanese/Asian styles. Smooth.
Source Kim Ruddock
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Like the name suggests, this background image consists of a pattern of dark bricks. It may be an option for you, if you are looking for something that looks like a brick wall for use as a background on web pages. It's not a masterpiece, but looks pretty nice when is tiled.
Source V. Hartikainen
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
A comeback for you: the popular Escheresque, now in black.
Source Patten
Light and tiny, just the way you like it.
Source Rohit Arun Rao
Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
Prismatic Abstract Geometric Background 4
Source GDJ