8 by 8 pixels, and just what the title says.
Source pixilated
Formed by heavily distorting part of a an image of a fish uploaded to Pixabay by GLady
Source Firkin
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Derived from an image that was uploaded to Pixabay by TheDigitalArtist
Source Firkin
Tile available in Inkscape using shift-alt-i on the selected rectangle
Source Firkin
Vertical lines with a bumpy, yet crisp, feel to it.
Source Raasa
From a drawing of the coat of arms of the Ottoman Empire on Wikimedia.
Source Firkin
Prismatic Abstract Line Art Pattern Background
Source GDJ
These dots are already worn for you, so you don’t have to.
Source Matt McDaniel
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
You were craving more leather, so I whipped this up by scanning a leather jacket.
Source Atle Mo
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
Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas
Prismatic Curved Diamond Pattern 4 No Background
Source GDJ
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
This background pattern contains a seamless texture of bark. It's not very realistic, but I think it looks quite nice.
Source V. Hartikainen
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo