This is the remix of an OCAL clipart called "Art Nouveau ornament" uploaded by "microcosme".Thanks.This is a seamless pattern of an Art Nouveau ornament.
Source Yamachem
This one is amazing, truly original. Go use it!
Source Viahorizon
Original seamless pattern with an Inkscape filter.
Source Firkin
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
You were craving more leather, so I whipped this up by scanning a leather jacket.
Source Atle Mo
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
A repeating background of beige (or is it more vanilla yellow) textured stripes. One more background with stripes.
Source V. Hartikainen
More bright luxury. This is a bit larger than fancy deboss, and with a bit more noise.
Source Viszt Péter
Colour version that is close to the original drawing uploaded to Pixabay by pencilparker.
Source Firkin
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
An abstract texture of black metal pipes (seamless).
Source V. Hartikainen
Dark, crisp and subtle. Tiny black lines on top of some noise.
Source Wilmotte Bastien
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin