Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
It was called Navy Blue, but I made it dark. You know, the way I like it.
Source Ethan Hamilton
Oh yes, it happened! A pattern in full color.
Source Atle Mo
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
Background formed from the original with an emboss effect
Source GDJ
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A very dark asfalt pattern based off of a photo taken with my iPhone.
Source Atle Mo
A seamless striped fabric-like texture colored in a dark reddish brown color.
Source V. Hartikainen
Based on an image that was uploaded to Pixabay by devanath
Source Firkin
Abstract Geometric Monochrome Pattern Prismatic No Background
Source GDJ
Alternative colour scheme for the original floral pattern.
Source Firkin
Here's a new gray "fabric" pattern. Use it as backgrounds for websites or for other purposes.
Source V. Hartikainen
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Same classic 45-degree pattern, dark version.
Source Luke McDonald
Fix side and a seamless pattern formed from circles.
Source SliverKnight
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.
Source Atle Mo
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
Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas