A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman
Inspired by a pattern I saw in a 19th century book. This seamless pattern was created from a square tile. To get the tile, select the pattern in Inkscape and use shift+alt+i.
Source Firkin
This one is amazing, truly original. Go use it!
Source Viahorizon
An abstract Background pattern of purple twisty patterns.
Source TikiGiki
Prismatic Floral Pattern 3 Variation 3 No Background
Source GDJ
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle 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
Zero CC tileable cork floor, photographed and made by me. CC0
Source Sojan Janso
Colorful Floral Background 3 No Black
Source GDJ
A seamless pattern formed from a square tile based on a jpg on Pixabay. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I.
Source Firkin
Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
Remixed from a vector adapted from a jpg on Pixabay. The tile this is constructed from can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
I’m starting to think I have a concrete wall fetish.
Source Atle Mo
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Remixed from a PNG that was uploaded to Pixabay by k_jprather
Source Firkin
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Vector version of a JPG that was uploaded to Pixabay by theasad121
Source Firkin
Prismatic Groovy Concentric Background 3 No Black
Source GDJ
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc