Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
Looks like an old wall. I guess that’s it then?
Source Viahorizon
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
Prismatic Snowflakes Pattern 3 No Background
Source GDJ
A seamless pattern the starting point for which was a 'light rays' rendering in Paint.net.
Source Firkin
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
A background formed from an image of an old tile on the New York Metropolitan Museum of Art website. To get the base tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
Prismatic Groovy Concentric Background 5 No Black
Source GDJ
Classic 45-degree pattern, light version.
Source Luke McDonald
Pixel by pixel, sharp and clean. Very light pattern with clear lines.
Source M.Ashok
Real snow that tiles, not easy. This is not perfect, but an attempt.
Source Atle Mo
A pale orange background pattern with glossy groove stripes.
Source V. Hartikainen
Prismatic Geometric Pattern Background No Black
Source GDJ
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
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 simple bump filter made upon request at irc #inkscape at freenode. Made a screen capture of the making here: https://youtu.be/TGAWYKVLxQw
Source Lazur URH
Prismatic Groovy Concentric Background 3 No Black
Source GDJ
Green Web Background, Seamless tile.
Source V. Hartikainen
You were craving more leather, so I whipped this up by scanning a leather jacket.
Source Atle Mo
Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic