With a name this awesome, how can I go wrong?
Source Nikolay Boltachev
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
A seamless pattern of dark bricks. Maybe it's not very realistic, but it looks good in my opinion.
Source V. Hartikainen
Textured Red Brown Plastic, Free Background Pattern. Although there's already enough plastic in our lives, let's bring it to the web too.)
Source V. Hartikainen
Can never have too many knitting patterns, especially as nice as this.
Source Victoria Spahn
One more brick pattern. A bit more depth to this one.
Source Benjamin Ward
8 by 8 pixels, and just what the title says.
Source pixilated
A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
Bright Multicolored Floral Background by Karen Arnold from PDP.
Source GDJ
A seamless background pattern of dark brown wood planks.
Source V. Hartikainen
A seamless pattern drawn originally in Paint.net by distorting a slice of background pattern 116 and copying the resulting triangle numerous times.
Source Firkin
Prismatic Abstract Line Art Pattern Background
Source GDJ
Geometric triangles seem to be quite hot these days.
Source Pixeden
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
This one is something special. I’d call it a flat pattern, too. Very well done, sir!
Source GetDiscount
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Here's a quite bright pink background pattern for use on websites. It doesn't look like a real fur, but it definitely resembles one.
Source V. Hartikainen
Abstract Arbitrary Geometric Background derived from an image on Pixabay.
Source GDJ