A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
A seamless texture of worn out "cardboard".
Source V. Hartikainen
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
A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
Prismatic Rounded Squares Grid 3 No Background
Source GDJ
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
Inspired by an image that was uploaded to Pixabay by geralt
Source Firkin
It has waves, so make sure you don’t get sea sickness.
Source CoolPatterns
The tile can be had by selecting the rectangle in Inkscape and using shift+alt+i. Remixed from a drawing in 'Flowers of Song', Frederick Weatherly, 1895.
Source Firkin
I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
Fix and cc0 to get the tile this is based on.
Source SliverKnight
I love these crisp, tiny, super subtle patterns.
Source Badhon Ebrahim
This one needs to be used in small areas; you can see it repeat.
Source Luca
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Nothing like a clean set of bed sheets, huh?
Source Badhon Ebrahim
ZeroCC tileable beechwood wood texture, generated in Neo Texture Edit by me. CC0
Source Sojan Janso
Zero CC tileable yellow craft paper; scanned and made by me. CC0
Source Sojan Janso
Might not be super subtle, but quite original in its form.
Source Alex Smith