CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
This background pattern contains worn out colorful stripes as a texture.
Source V. Hartikainen
A heavy hitter at 400x400px, but lovely still.
Source Breezi
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
The image depicts a seamless pattern of a tortoise in tortoiseshell (hexagon).
Source Yamachem
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Zero CC tileable hard cover cells, skin like, book texture. 4K, Scanned and made by me CC0
Source Sojan Janso
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
Can’t believe we don’t have this in the collection already! Slick woven pattern with crisp details.
Source Max Rudberg
A free green background pattern with a pattern of rhombuses on a seamless texture. Feel free to use it as a tiled background image on your web site.
Source V. Hartikainen
Alternative colour scheme for the original floral pattern.
Source Firkin
Abstract Geometric Monochrome Pattern Prismatic No Background
Source GDJ
This light yellow background pattern consists of an irregular pattern of spots. Here's a light background pattern with yellowish tint.
Source V. Hartikainen
This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
A seamless web texture of "green stone".
Source V. Hartikainen
Remixed from a drawing in 'Kulturgeschichte der Deutschen im Mittelalter' Franz von Loeher, 1891. The unit tile can be had by selecting the rectangle in Inkscape and using shift-alt-i
Source Firkin
Prismatic Abstract Line Art Pattern Background
Source GDJ
Dark, crisp and subtle. Tiny black lines on top of some noise.
Source Wilmotte Bastien
Another fairly simple design drawn in Paint.net and vectorized in Inkscape.
Source Firkin
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
Prismatic Abstract Background Design
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Inspired by a pattern seen on a public domain image of a very old tile. To get the unit cell, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.
Source Atle Mo
Remixed from a drawing in 'An Index to Deering's Nottinghamia Vetus et Nova', Rupert Chicken, 1899. The unit tile can be had by selecting the rectangle in Inkscape and using shift-alt-i
Source Firkin