ZeroCC tileable stone texture, edited from pixabay. CC0
Source Sojan Janso
This metal background pattern resembles a metal plate with rivets. Solid rivets on a metal plate.
Source V. Hartikainen
Here's a camo print with more tan and less green, such as might be used in a desert scenario. This is tileable, so it can be used as a wallpaper or background.
Source Eady
This is the remix of "blue wave-seigaiha".The image depicts a seamless pattern of the front upper part of Japanese five yen coin which is used currently.This design represents a rice with ripe golden ears.
Source Yamachem
Background formed from the iconic plastic construction bricks that gave me endless hours of fun when I was a lad.
Source Firkin
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
Prismatic Groovy Concentric Background 3 No Black
Source GDJ
The file was named striped lens, but hey – Translucent Fibres works too.
Source Angelica
Floral patterns will never go out of style, so enjoy this one.
Source Lasma
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
Prismatic Hypnotic Pattern 2 No Background
Source GDJ
A pattern drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
Alternative colour scheme for the original floral pattern.
Source Firkin
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
A simple example on using clones. You can generate a nice base for a pattern fill quickly with it.
Source Lazur URH
Could be paper, could be a Polaroid frame – up to you!
Source Chaos
Prismatic Curved Diamond Pattern No Background
Source GDJ
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
Prismatic Snowflakes Pattern 3 No Background
Source GDJ
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
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
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Remixed from a drawing in 'Очерки Русской Исторіи въ памятникахъ быта', Petr Polevoi, 1879.
Source Firkin