Super subtle indeed, a medium gray pattern with tiny dots in a grid.
Source Designova
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
You guessed it – looks a bit like cloth.
Source Peax Webdesign
Derived from a PNG that was uploaded to Pixabay by nutkitten
Source Firkin
Inspired by a 1930s wallpaper pattern I saw on TV.
Source Firkin
Submitted in a cream color, but you know how I like it.
Source Devin Holmes
This one is super crisp at 2X. Lined paper with some dust and scratches.
Source HQvectors
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Not sure if this is related to the Nami you get in Google image search, but hey, it’s nice!
Source Dertig Media
Wild Oliva or Oliva Wilde? Darker than the others, sort of a medium dark pattern.
Source Badhon Ebrahim
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Dark wooden pattern, given the subtle treatment. based on texture from Cloaks. https://cloaks.deviantart.com
Source Atle Mo
A seamless texture of worn out "cardboard".
Source V. Hartikainen
Prismatic Curved Diamond Pattern 2 No Background
Source GDJ
Dark, square, clean and tidy. What more can you ask for?
Source Jaromír Kavan
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I. Version with black background.
Source Firkin
Black And White Floral Pattern Background from PDP.
Source GDJ