After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers
Inspired by a drawing seen in 'City of Liverpool', James Picton, 1883.
Source Firkin
A simple but elegant classic. Every collection needs one of these.
Source Christopher Burton
Prismatic Groovy Concentric Background 2 No Black
Source GDJ
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić
It looks very nice I think.
Source V. Hartikainen
An abstract texture of black metal pipes (seamless).
Source V. Hartikainen
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
ZeroCC tileable mossy (lichen) stone texture, edited from pixabay. CC0
Source Sojan Janso
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
A background pattern with a look of rough fabric.
Source V. Hartikainen
Prismatic Geometric Tessellation Pattern No Background
Source GDJ
This is a hot one. Small, sharp and unique.
Source GraphicsWall
Prismatic Curved Diamond Pattern 2 No Background
Source GDJ
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i
Source Firkin
Prismatic Abstract Line Art Pattern Background
Source GDJ
Not the Rebel alliance, but a dark textured pattern.
Source Hendrik Lammers
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i
Source Firkin
More leather, and this time it’s bigger! You know, in case you need that.
Source Elemis
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
Oh yes, it happened! A pattern in full color.
Source Atle Mo
A very slick dark rubber grip pattern, sort of like the grip on a camera.
Source Sinisha
Sort of like the Photoshop transparent background, but better!
Source Alex Parker
This was formed by distorting an image of a background on Pixabay.
Source Firkin
This beige background pattern resembles a concrete wall with engravings or something similar to it.
Source V. Hartikainen
A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen