Not so subtle. These tileable wood patterns are very useful.
Source Elemis
Derived from a PNG that was uploaded to Pixabay by nutkitten
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
This is a seamless pattern which is derived from a flower petal image.
Source Yamachem
Zero CC tileable wood texture, made by me procedurally in Neo Texture Edit.
Source Sojan Janso
This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
The image depicts a seamless pattern of Japanese Edo pattern called "kikkou-matsu" or "亀甲松" meaning " tortoiseshell-pinetree".The real pinetree is like this: https://jp.pinterest.com/pin/500744052301065077/
Source Yamachem
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Here's a subtle marble-like background for use on websites.
Source V. Hartikainen
People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
Wasn't satisfied with the original's colouring. Too much component transfer and colormatrixes yet the results are lacking a bit. So this time it is a simple black to transparent fade, making it possible remixing easily once there will be other blending modes supported as well. Probably in inkscape 0.92.
Source Lazur URH
Zero CC tileable bark texture, photographed and made by me. CC0
Source Sojan Janso
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
A repeating background with wood/straw like texture.
Source V. Hartikainen
Pixel by pixel, sharp and clean. Very light pattern with clear lines.
Source M.Ashok
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
The image depicts a pattern of regular hexagon.As I made to use it for myself,I want to others to use it.Speaking about the ratio of the image, height : width = 2 : √3(1.732...)Ridiculous to say,I realized later that this image is not honey comb pattern.I have to slide the second row.
Source Yamachem
Nasty or not, it’s a nice pattern that tiles. Like they all do.
Source Badhon Ebrahim
Abstract Tiled Background Extended 10
Source GDJ
Background Wall, Art Abstract, Star Well & CC0 texture.
Source Ractapopulous
The Grid. A digital frontier. I tried to picture clusters of information as they traveled through the computer.
Source Haris Šumić