From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Not even 1kb, but very stylish. Gray thin lines.
Source Struck Axiom
Abstract Tiled Background Extended 11
Source GDJ
A seamlessly tile-able grunge background image.
Source V. Hartikainen
The classic notebook paper with horizontal stripes.
Source Are Sundnes
This background image has seamless texture that resembles a surface of gray stone.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i
Source Firkin
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Not sure if this is related to the Nami you get in Google image search, but hey, it’s nice!
Source Dertig Media
Nicely crafted paper pattern, although a bit on the large side (500x593px).
Source Blaq Annabiosis
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
Prismatic Triangular Seamless Pattern III With Background
Source GDJ
Remixed from a raster on Pixabay that was uploaded by ArtsyBee.
Source Firkin
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A seamless web texture of "green stone".
Source V. Hartikainen