Seamless pattern made from a tile that can be obtained in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
Stefan is hard at work, this time with a funky pattern of squares.
Source Stefan Aleksić
U.S.-based National Fire Protection Association standard fire diamond for flagging risks posed by hazardous materials. The red diamond has a number 0-4 depending on flammability. The blue diamond has a number 0-4 depending on health hazard. The yellow has a number 0-4 depending on reactivity. the white square has a special notice, e.g OX for oxidizer.
Source Firkin
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
Zero CC tileable hard cover green book, scanned and made by me. CC0
Source Sojan Janso
A beautiful dark padded pattern, like an old classic sofa.
Source Chris Baldie
A free seamless background with pink spots.
Source V. Hartikainen
Remixed from a drawing that was uploaded to Pixabay by DavidZydd
Source Firkin
Prismatic Polka Dots 3 No Background
Source GDJ
Derived from a PNG that was uploaded to Pixabay by nutkitten
Source Firkin
From a drawing in 'Hyde Park from Domesday-Book to date', John Ashton, 1896.
Source Firkin
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
A yellow tiled background... Blurriness, bokeh effect and rectangles pattern in one mix.
Source V. Hartikainen
Remixed from a drawing in 'Analecta Eboracensia', Thomas Widdrington, 1897.
Source Firkin
Spice up your next school project with this icon background.
Source Swetha
Everyone needs some stardust. Sprinkle it on your next project.
Source Atle Mo
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin