Not so subtle. These tileable wood patterns are very useful.
Source Elemis
Here's a new background image for websites with a seamless pink texture. It should look beautiful with website themes where light pink background is needed. The background is seamless, therefore it should be used as a tiled background.
Source V. Hartikainen
Zero CC tileable hard cover green book, scanned and made by me. CC0
Source Sojan Janso
Prismatic Geometric Pattern Background 2
Source GDJ
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
An abstract web texture of a polished blue stone (or does it look more like ice).
Source V. Hartikainen
Here's a new paper-like background for free use on personal and commercial projects (this applies to all background patterns here).
Source V. Hartikainen
From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.
Source Firkin
From a drawing in 'Two Women in the Klondike', Mary Hitchcock, 1899.
Source Firkin
It’s okay to be square! A nice light gray pattern with random squares.
Source Waseem Dahman
A repeating background with dark brown stone-like texture and abstract pattern that looks like tree trunks.
Source V. Hartikainen
White little knobs, coming in at 10x10px. Sweet!
Source Amos
Everyone loves a diamond, right? Make your site sparkle.
Source AJ Troxell
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
Prismatic Curved Diamond Pattern 8 No Background
Source GDJ
Prismatic Groovy Concentric Background No Black
Source GDJ
This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Abstract Tiled Background Extended 8
Source GDJ
This is the remix of "Colorful Floral Pattern Background 3" uploaded by "GDJ". Thanks.
Source Yamachem
A seamless pattern recreated from an image on Pixabay. It is reminiscent of parquet flooring and is formed from a square tile, which can be recovered in Inkscape by selecting the ungrouped rectangle and using shift-alt-I together.
Source Firkin