Not so subtle. These tileable wood patterns are very useful.
Source Elemis
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Prismatic Groovy Concentric Background 4
Source GDJ
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A bit like some carbon, or knitted netting if you will.
Source Anna Litvinuk
Background Wall, Art Abstract, Blue Well & CC0 texture.
Source Ractapopulous
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Dark blue concrete wall with some small dust spots.
Source Atle Mo
Prismatic Snowflakes Pattern 2 No Background
Source GDJ
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
Dark, square, clean and tidy. What more can you ask for?
Source Jaromír Kavan
Seamless Prismatic Pythagorean Line Art Pattern No Background. A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
This was formed by distorting an image of a background on Pixabay.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
You know you love wood patterns, so here’s one more.
Source Richard Tabor
An aged paper background tile with smeared and pressed text.
Source V. Hartikainen
Otis Ray Redding was an American soul singer-songwriter, record producer, arranger, and talent scout. So you know.
Source Thomas Myrman
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin