This ladies and gentlemen, is texturetastic! Love it.
Source Adam Pickering
There are many carbon patterns, but this one is tiny.
Source Designova
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
You could get a bit dizzy from this one, but it might come in handy.
Source Dertig Media
From a drawing in 'Studies for Stories', Jean Ingelow, 1864.
Source Firkin
Background formed from the original with an emboss effect
Source GDJ
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
A pattern drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
Bright Multicolored Floral Background by Karen Arnold from PDP.
Source GDJ
Remixed from a JPG that was uploaded to Pixabay by theasad121
Source Firkin
From a drawing in 'Real Sailor-Songs', John Ashton, 1891.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
This tiled background comes in red and consists of tiles that look like gemstones. It is more for blogs or social profiles, I think.
Source V. Hartikainen
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Luxury pattern, looking like it came right out of Paris.
Source Daniel Beaton
From a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley