The image is a seamless pattern of a fishnet.
Source Yamachem
Prismatic Abstract Geometric Background 4
Source GDJ
A repeatable image with dark background and metal grid pattern.
Source V. Hartikainen
CC0 and seamless wellington boot pattern.
Source SliverKnight
Seamless pattern formed from a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Sharp pixel pattern, just like the good old days.
Source Paridhi
Medium gray fabric pattern with 45-degree lines going across.
Source Atle Mo
One more updated pattern. Not really carbon fiber, but it’s the most popular pattern, so I’ll give you an extra choice.
Source Atle Mo
Clean and crisp lines all over the place. Wrap it up with this one.
Source Dax Kieran
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Bright Multicolored Floral Background by Karen Arnold from PDP.
Source GDJ
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Detailed but still subtle and quite original. Lovely gray shades.
Source Kim Ruddock
Alternative colour scheme for the original floral pattern.
Source Firkin
This is a remix of "blue wave-seigaiha".I hope this subtle color version of Seigaiha would be suitable for background .
Source Yamachem
Black brick wall pattern. Brick your site up!
Source Alex Parker
Remixed from a JPG that was uploaded to Pixabay by susanlu4esm
Source Firkin
The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
This one needs to be used in small areas; you can see it repeat.
Source Luca
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
A pale orange background pattern with glossy groove stripes.
Source V. Hartikainen