To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A simple circle. That’s all it takes. This one is even transparent, for those who like that.
Source Saqib
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
From a drawing in 'Studies for Stories', Jean Ingelow, 1864.
Source Firkin
Prismatic Abstract Geometric Background 4
Source GDJ
Not the most creative name, but it’s a good all-purpose light background.
Source Dmitry
Seamless Light Background Texture.
Source V. Hartikainen
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
A new take on the black linen pattern. Softer this time.
Source Atle Mo
A large (588x375px) sand-colored pattern for your ever-growing collection. Shrink at will.
Source Alex Tapein
You know, tiny and sharp. I’m sure you’ll find a use for it.
Source Atle Mo
This is a remix of "geometrical pattern 01".
Source Yamachem
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
ZeroCC tileabel stone granite texture, edited from pixabay. CC0
Source Sojan Janso
No idea what Nistri means, but it’s a crisp little pattern nonetheless.
Source Markus Reiter
Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
More in the paper realm, this time with fibers.
Source Jorge Fuentes
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin