Produced using the clouds, flames and glass blocks plug-ins in Paint.net and the resulting .PNG vectorised with Vector Magic.
Source Firkin
Fix and cc0 to get the tile this is based on.
Source SliverKnight
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
Psychedelic Geometric Background No Black
Source GDJ
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
ZeroCC tileable stone texture, edited from pixabay, CC0
Source Sojan Janso
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
The image is a remix of "edo pattern-samekomon".I changed the color of dots from black to white and added BG in light-yellow.
Source Yamachem
Tiny, tiny 3D cubes. Reminds me of the good old pattern from k10k.
Source Etienne Rallion
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
The image depicts a seamless pattern which was made using stripe-like things including borders.I used OCAL cliparts called "Blue Greek Key With Lines Border" uploaded by "GR8DAN" and "daisy border" uploaded by "johnny_automatic".Thanks.
Source Yamachem
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
Lovely pattern with splattered vintage speckles.
Source David Pomfret
Seamless Prismatic Geometric Pattern With Background
Source GDJ
Same classic 45-degree pattern, dark version.
Source Luke McDonald
It has waves, so make sure you don’t get sea sickness.
Source CoolPatterns
A dark striped seamless pattern suitable for use as a background on websites.
Source V. Hartikainen
From a drawing in 'Storia del Palazzo Vecchio in Firenze', Aurelio Gotti, 1889.
Source Firkin
A seamless marble-like texture colored in light blue.
Source V. Hartikainen
A rusty grunge background for websites. Feel free to use it in your site's theme.
Source V. Hartikainen
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
Prismatic Polka Dots 3 No Background
Source GDJ