CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Nicely crafted paper pattern, although a bit on the large side (500x593px).
Source Blaq Annabiosis
Remixed from a design on Pixabay. To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
This is the remix of "Strawberry Pattern Background" uploaded by "GDJ". Thanks. I realigned strawberries so as to get seamless and changed the BG color.
Source Yamachem
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
One can never have too few rice paper patterns, so here is one more.
Source Atle Mo
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Zero CC tileable ground cracked, crackled, texture, made by me.
Source Sojan Janso
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
Zero CC tileable brick texture, photographed and made by me. CC0
Source Sojan Janso
A subtle shadowed checkered pattern. Increase the lightness for even more subtle sexiness.
Source Josh Green
Original seamless pattern with an Inkscape filter.
Source Firkin
Light gray paper pattern with small traces of fiber and some dust.
Source Atle Mo
A repeatable image with dark background and metal grid pattern.
Source V. Hartikainen
A seamless pattern of dark bricks. Maybe it's not very realistic, but it looks good in my opinion.
Source V. Hartikainen
Remixed from a drawing in 'The March of Loyalty', Letitia MacClintock, 1884.
Source Firkin
Nasty or not, it’s a nice pattern that tiles. Like they all do.
Source Badhon Ebrahim
Dark, lines, noise, tactile. You get the drift.
Source Anatoli Nicolae
Another fairly simple design drawn in Paint.net and vectorized in Inkscape.
Source Firkin
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin