Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Used correctly, this could be nice. Used in a bad way, all hell will break loose.
Source Atle Mo
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
More in the paper realm, this time with fibers.
Source Jorge Fuentes
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Alternative colour scheme for the original floral pattern.
Source Firkin
ZeroCC tileable moss texture, photographed and made by me. CC0
Source Sojan Janso
Washi (和紙?) is a type of paper made in Japan. Here’s the pattern for you!
Source Carolynne
Continuing the geometric trend, here is one more.
Source Mike Warner
Inspired by a drawing seen in 'City of Liverpool', James Picton, 1883.
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
Not sure if this is related to the Nami you get in Google image search, but hey, it’s nice!
Source Dertig Media
A comeback for you: the popular Escheresque, now in black.
Source Patten
More in the paper realm, this time with fibers.
Source Jorge Fuentes
Remixed from an image on Pixabay, the original having been uploaded by darkmoon1968.
Source Firkin
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Prismatic Abstract Line Art Pattern Background 2
Source GDJ
A background pattern with green vertical stripes. A new striped background pattern. This time a green one.
Source V. Hartikainen
From a drawing in 'An Old Maid's Love. A Dutch tale told in English', Maarten Maartens, 1891.
Source Firkin