A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
One more brick pattern. A bit more depth to this one.
Source Benjamin Ward
A pale orange background pattern with glossy groove stripes.
Source V. Hartikainen
Have you wondered about how it feels to be buried alive? Here is the pattern for it.
Source Hendrik Lammers
This one needs to be used in small areas; you can see it repeat.
Source Luca
Kaleidoscope Prismatic Abstract No Background
Source GDJ
If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
A background pattern with wavy green vertical stripes. This one has green stripes on a white background. Download if you like it.
Source V. Hartikainen
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
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua