I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
A seamless background texture of old cardboard.
Source V. Hartikainen
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
A light gray background pattern with seamless fabric-like texture and almost unnoticeable stripes.
Source V. Hartikainen
From a drawing in 'A Guide to the Guildhall of the City of London', John Baddeley, 1898.
Source Firkin
Prismatic Hypnotic Pattern 2 No Background
Source GDJ
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
The base gradient edited so now more details are rendered.
Source Lazur URH
By popular request, an outline version of the pentagon pattern.
Source Atle Mo
Lovely pattern with splattered vintage speckles.
Source David Pomfret
Nicely crafted paper pattern, although a bit on the large side (500x593px).
Source Blaq Annabiosis
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
Remixed from a drawing in 'Analecta Eboracensia', Thomas Widdrington, 1897.
Source Firkin
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A seamless pattern based on a rectangular tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Seamless Background For Websites. It has a texture similar to cork-board.
Source V. Hartikainen
With a name this awesome, how can I go wrong?
Source Nikolay Boltachev
Background formed from the iconic plastic construction bricks that gave me endless hours of fun when I was a lad.
Source Firkin
This background image has seamless texture that resembles a surface of gray stone.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Zero CC tileable yellow craft paper; scanned and made by me. CC0
Source Sojan Janso
Alternative colour scheme for the original floral pattern.
Source Firkin