Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
Not the most creative name, but it’s a good all-purpose light background.
Source Dmitry
Might not be super subtle, but quite original in its form.
Source Alex Smith
A free seamless background texture that looks like a brown stone wall.
Source V. Hartikainen
Fake or not, it’s quite luxurious.
Source Factorio.us Collective
Remixed from a drawing in 'Incidents on a Journey through Nubia to Darfoor', F. Ensor, 1891.
Source Firkin
Zero CC tileable grass texture, photographed and made by me. CC0
Source Sojan Janso
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Remixed from a PNG that was uploaded to Pixabay by k_jprather
Source Firkin
I love these crisp, tiny, super subtle patterns.
Source Badhon Ebrahim
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Prismatic Curved Diamond Pattern 2 No Background
Source GDJ
Detailed but still subtle and quite original. Lovely gray shades.
Source Kim Ruddock
White circles connecting on a light gray background.
Source Mark Collins
Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
Brushed aluminum, in a bright gray version. Lovely 2X as well.
Source Andre Schouten
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
Prismatic Groovy Concentric Background 5 No Black
Source GDJ
A seamless textured paper for backgrounds. Colored in pale orange hues.
Source V. Hartikainen
As simple and subtle as it gets. But sometimes that’s just what you want.
Source Designova
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
This one is super crisp at 2X. Lined paper with some dust and scratches.
Source HQvectors
An abstract texture of water. It's not perfect, but will do. You may download if you like it.
Source V. Hartikainen