Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
A repeating background with dark brown stone-like texture and abstract pattern that looks like tree trunks.
Source V. Hartikainen
If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
Just like your old suit, all striped and smooth.
Source Alex Berkowitz
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Remixed from a drawing in 'Analecta Eboracensia', Thomas Widdrington, 1897.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
You know you love wood patterns, so here’s one more.
Source Richard Tabor
Prismatic Abstract Geometric Background 5
Source GDJ
Sort of like the back of a wooden board. Light, subtle, and stylish, just the way we like it!
Source Nikolalek
Prismatic Curved Diamond Pattern 7 No Background
Source GDJ
Prismatic Abstract Geometric Background 4
Source GDJ
Inspired by a pattern seen on a public domain image of a very old tile. To get the unit cell, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Alternative colour scheme for the original floral pattern.
Source Firkin
From a drawing in 'Studies for Stories', Jean Ingelow, 1864.
Source Firkin
Sharp pixel pattern looking like some sort of fabric.
Source Dmitry
A seamless pattern formed from cross 4. To get the original tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8