A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
It’s like Shine Dotted’s sister, only rotated 45 degrees.
Source mediumidee
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
Paper model of a tetrahedron. Modelo de papel de um tetraedro.
Source laobc
Fake or not, it’s quite luxurious.
Source Factorio.us Collective
Number 2 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
A seamless light gray paper texture with horizontal double lines.
Source V. Hartikainen
A pattern formed from a squared tile. The tile can be accessed 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
Remixed from a raster on Pixabay that was uploaded by ArtsyBee.
Source Firkin
Pattern formed from simple shapes. Black version.
Source Firkin
Prismatic Abstract Line Art Pattern Background 2
Source GDJ
You know you love wood patterns, so here’s one more.
Source Richard Tabor
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
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
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
A version without colours blended together to give a different look.
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
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra