Not even 1kb, but very stylish. Gray thin lines.
Source Struck Axiom
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
There are many carbon patterns, but this one is tiny.
Source Designova
Prismatic Hypnotic Pattern No Background
Source GDJ
A seamless texture of worn out "cardboard".
Source V. Hartikainen
Light gray version of the Binding pattern that looks a bit like fabric.
Source Newbury
Imagine you zoomed in 1000X on some fabric. But then it turned out to be a skeleton!
Source Angelica
Number 2 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Sort of like the back of a wooden board. Light, subtle, and stylish, just the way we like it!
Source Nikolalek
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
This ons is quite old school looking. Retro, even. I like it.
Source Arno Declercq
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
A fun-looking elastoplast/band-aid pattern. A hint of orange tone in this one.
Source Josh Green
Prismatic Abstract Background Design
Source GDJ
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Just a nice looking textured pattern with faded blue stripes. Well, that's it for today... one background a day, as usual.
Source V. Hartikainen
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
A pale yellow background pattern with vertical stripes. The stripes are partially faded. I think this background image turned out pretty well, especially those faded stripes.
Source V. Hartikainen