Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Nice little grid. Would work great as a base on top of some other patterns.
Source Arno Gregorian
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A pale yellow background pattern with vertical stripes. The stripes are partially faded. I think this background image turned out pretty well, especially those faded stripes.
Source V. Hartikainen
Dark wooden pattern, given the subtle treatment. based on texture from Cloaks. https://cloaks.deviantart.com
Source Atle Mo
This light yellow background pattern consists of an irregular pattern of spots. Here's a light background pattern with yellowish tint.
Source V. Hartikainen
The image a seamless pattern of a wire-mesh fence.I want you to use this pattern as a lower layer.
Source Yamachem
A pale orange background pattern with glossy groove stripes.
Source V. Hartikainen
The starting point for this was a texture drawn with the 'Radial Colors' plug-in in Paint.net.
Source Firkin
Prismatic Abstract Geometric Background 3
Source GDJ
Alternative colour scheme. Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A seamless pattern formed from background pattern 102
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
I love these crisp, tiny, super subtle patterns.
Source Badhon Ebrahim
Derived from an image that was uploaded to Pixabay by Kaz
Source Firkin
A pattern derived from repeating unit cells each derived from part of a mosaic in paint.net. The starting point for the mosaic was a picture of some prawns!
Source Firkin
A bit simplified version. Although it could be edited out to be simpler. Anyway, this time the tiling is converted to a pattern fill -which is using clipping for the tile's edges.
Source Lazur URH
More bright luxury. This is a bit larger than fancy deboss, and with a bit more noise.
Source Viszt Péter
Sharp pixel pattern, just like the good old days.
Source Paridhi
Background Wall, Art Abstract, Watercolor Vintage style CC0 texture.
Source Ractapopulous
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A classic dark tile for a bit of vintage darkness.
Source Listvetra