Continuing the geometric trend, here is one more.
Source Mike Warner
A textured blue background pattern with vertical stripes.
Source V. Hartikainen
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
Retro Circles Background 4 No Black
Source GDJ
Super subtle indeed, a medium gray pattern with tiny dots in a grid.
Source Designova
A seamless texture of a rough concrete surface.
Source V. Hartikainen
Remixed from an image that was uploaded to Pixabay by Pixeline
Source Firkin
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Inspired by a pattern found in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Seamless pattern made from a tile that can be obtained in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Just like the black maze, only in light gray. Duh.
Source Peax
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857
Source Firkin
A re-make of the Gradient Squares pattern.
Source Dimitar Karaytchev
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
An alternative colour scheme to the original seamless pattern.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
White circles connecting on a light gray background.
Source Mark Collins