A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
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
From a drawing in 'Hyde Park from Domesday-Book to date', John Ashton, 1896.
Source Firkin
Seamless Prismatic Geometric Pattern With Background
Source GDJ
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
The name is totally random, but hey, it sounds good.
Source Atle Mo
A criss-cross pattern similar to one I saw mown into a sports field.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
The classic 45-degree diagonal line pattern, done right.
Source Jorick van Hees
8 by 8 pixels, and just what the title says.
Source pixilated
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Light and tiny, just the way you like it.
Source Rohit Arun Rao
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 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
Original seamless pattern with an Inkscape filter.
Source Firkin