This is a hot one. Small, sharp and unique.
Source GraphicsWall
Subtle scratches on a light gray background.
Source Andrey Ovcharov
White circles connecting on a light gray background.
Source Mark Collins
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Here's a brown background pattern with subtle stripes. I hope you'll like the color. If not, feel free to change it using an image editor, if you know how of course. Personally, I'm using GIMP to create these backgrounds.
Source V. Hartikainen
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
Sounds like something from World of Warcraft. Has to be good.
Source Tony Kinard
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
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
An attempt for cleaning up the original image in a few steps.
Source Lazur URH
Prismatic Snowflakes Pattern 3 No Background
Source GDJ
Sharp pixel pattern, just like the good old days.
Source Paridhi
Love the style on this one, very fresh. Diagonal diamond pattern. Get it?
Source INS
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Inspired by a drawing in 'Poems', James Smith, 1881.
Source Firkin
This beige background pattern resembles a concrete wall with engravings or something similar to it.
Source V. Hartikainen
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Prismatic Floral Background No Black
Source GDJ
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
Abstract Geometric Monochrome Pattern Prismatic No Background
Source GDJ
Adapted from an image that was uploaded to Pixabay by Anerma.
Source Firkin
Prismatic Geometric Tessellation Pattern 3 No Background
Source GDJ
Here is a new seamless wood texture for using as blog or website backgrounds.
Source V. Hartikainen