Not so subtle. These tileable wood patterns are very useful.
Source Elemis
A seamless pattern the starting point for which was a 'light rays' rendering in Paint.net.
Source Firkin
An interesting dark spotted pattern at an angle.
Source Hendrik Lammers
This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley
Colour version of the original pattern.
Source Firkin
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
An alternative colour scheme for the original seamless texture formed from an image on Pixabay.
Source Firkin
Detailed but still subtle and quite original. Lovely gray shades.
Source Kim Ruddock
A free background tile with a pattern of pink bump dots. This background tile is sweet! Moreover, it's designed for use as website backgrounds.
Source V. Hartikainen
Paper model of a tetrahedron. Modelo de papel de um tetraedro.
Source laobc
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
More in the paper realm, this time with fibers.
Source Jorge Fuentes
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
Inspired by a pattern I saw in a 19th century book. This seamless pattern was created from a square tile. To get the tile, select the pattern in Inkscape and use shift+alt+i.
Source Firkin
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Here's a seamless brown cork board background texture. Feel free to download or reshare if you like.
Source V. Hartikainen
Remixed from a drawing in 'Line and form", Walter Crane, 1914.
Source Firkin
I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
From a drawing in 'Heroes of North African Discovery', Nancy Meugens, 1894.
Source Firkin
Continuing the geometric trend, here is one more.
Source Mike Warner
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Light gray paper pattern with small traces of fiber and some dust.
Source Atle Mo