A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
A series of 5 patterns. That’s what the P stands for, if you didn’t guess it.
Source Dima Shiper
A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman
Dark blue concrete wall with some small dust spots.
Source Atle Mo
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A light gray wall or floor (you decide) of concrete.
Source Atle Mo
8 by 8 pixels, and just what the title says.
Source pixilated
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
Remixed from a drawing in 'Canadian forest industries July-December', 1915
Source Firkin
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
Used the 6th circle pattern designed by Viscious-Speed to create a print that can be used for card making or scrapbooking. Save as a PDF file for the best printing option.
Source Lovinglf
A pale yellow background pattern with vertical stripes. The stripes are partially faded. I think this background image turned out pretty well, especially those faded stripes.
Source V. Hartikainen
ZeroCC tileable stone texture, edited from pixabay. CC0
Source Sojan Janso
Derived from a drawing in 'The Murmur of the Shells', Samuel Cowen, 1879.
Source Firkin
Prismatic Rounded Squares Grid 4 No Background
Source GDJ
A free seamless background with pink spots.
Source V. Hartikainen