Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
Feel free to download and use it, or see the rest of the dark background patterns that I have made. Anyway, I hope you will find something that you like.
Source V. Hartikainen
A repeating background of beige (or is it more vanilla yellow) textured stripes. One more background with stripes.
Source V. Hartikainen
From a drawing in 'Storia del Palazzo Vecchio in Firenze', Aurelio Gotti, 1889.
Source Firkin
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
A repeating background with dark brown stone-like texture and abstract pattern that looks like tree trunks.
Source V. Hartikainen
Derived from an image that was uploaded to Pixabay by darkmoon1968
Source Firkin
The original enhanced with one of Inkscapes's filters.
Source Firkin
More bright luxury. This is a bit larger than fancy deboss, and with a bit more noise.
Source Viszt Péter
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
Sometimes you just need the simplest thing.
Source Fabricio
This reminds me of Game Cube. A nice light 3D cube pattern.
Source Sander Ottens
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.
Source Firkin
An abstract texture of black metal pipes (seamless).
Source V. Hartikainen
From a drawing in 'An Old Maid's Love. A Dutch tale told in English', Maarten Maartens, 1891.
Source Firkin
Inspired by a drawing seen in 'City of Liverpool', James Picton, 1883.
Source Firkin
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
Vector version of a JPG that was uploaded to Pixabay by theasad121
Source Firkin