The image is a seamless pattern of a fishnet.
Source Yamachem
Light honeycomb pattern made up of the classic hexagon shape.
Source Federica Pelzel
Bright gray tones with a hint of some metal surface.
Source Hendrik Lammers
Dark wooden pattern, given the subtle treatment. based on texture from Cloaks.
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Formed by heavily distorting part of a an image of a fish uploaded to Pixabay by GLady
Source Firkin
This one resembles a black concrete wall when is tiled. It should look great, at least with dark website themes.
Source V. Hartikainen
Abstract Tiled Background Extended 12
Source GDJ
Dark wooden pattern, given the subtle treatment. based on texture from Cloaks. https://cloaks.deviantart.com
Source Atle Mo
Prismatic Abstract Line Art Pattern Background 2
Source GDJ
A free seamless background with pink spots.
Source V. Hartikainen
Prismatic Groovy Concentric Background 3 No Black
Source GDJ
Super dark, crisp and detailed. And a Kill Bill reference.
Source Badhon Ebrahim
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A background tile for web with abstract repeating texture of dark "stone wall".
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
Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
This one needs to be used in small areas; you can see it repeat.
Source Luca
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Vertical lines with a bumpy, yet crisp, feel to it.
Source Raasa
A bit like smudged paint or some sort of steel, here is scribble light.
Source Tegan Male
Clean and crisp lines all over the place. Wrap it up with this one.
Source Dax Kieran
A seamless pattern with a unit cell drawn as a bitmap in Paint.net and vectorized in Vector Magic.
Source Firkin
Sharp pixel pattern, just like the good old days.
Source Paridhi