I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
A seamless pattern with green and yellow diagonal lines on top of a white dotted background.
Source V. Hartikainen
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
Remixed from a JPG that was uploaded to Pixabay by susanlu4esm
Source Firkin
You could get a bit dizzy from this one, but it might come in handy.
Source Dertig Media
Super simple but very nice indeed. Gray with vertical stripes.
Source Merrin Macleod
This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
A seamless pattern formed from a tile made from ornament 22. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Alternative colour scheme for the original floral pattern.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A hint of orange color, and some crossed and embossed lines.
Source Adam Anlauf
Prismatic Abstract Geometric Background 5
Source GDJ
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
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
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
Actually, there's no clouds in it, but I think it looks quite nice.
Source V. Hartikainen