Here's a brown background pattern with subtle stripes. I hope you'll like the color. If not, feel free to change it using an image editor, if you know how of course. Personally, I'm using GIMP to create these backgrounds.
Source V. Hartikainen
Prismatic Curved Diamond Pattern 2 No Background
Source GDJ
Seamless SVG vector and JPG backgrounds with faded diagonal stripes. The colors are editable.
Source V. Hartikainen
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
This one needs to be used in small areas; you can see it repeat.
Source Luca
Dark, square, clean and tidy. What more can you ask for?
Source Jaromír Kavan
Pixel by pixel, sharp and clean. Very light pattern with clear lines.
Source M.Ashok
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
To get the tile this is made up from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
The tile this is formed from can be retrieved in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin
Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
A background pattern with green vertical stripes. A new striped background pattern. This time a green one.
Source V. Hartikainen
This is a more minute version of "fishnet 01".The image depicts a seamless pattern of a fishnet with a plenty of fish.It may be a lucky charm for fishermen.
Source Yamachem
It was called Navy Blue, but I made it dark. You know, the way I like it.
Source Ethan Hamilton
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Light gray grunge wall with a nice texture overlay.
Source Adam Anlauf
Submitted in a cream color, but you know how I like it.
Source Devin Holmes
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Background pattern made in "Grunge-Like" style. Available in both SVG and JPG formats. Edit to your needs then click the download button.
Source V. Hartikainen