Inspired by this, I came up with this pattern. Madness!
Source Atle Mo
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
Prismatic Snowflakes Pattern No Background
Source GDJ
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
Inspired by a drawing in 'Poems', James Smith, 1881.
Source Firkin
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
I have no idea what J Boo means by this name, but hey – it’s hot.
Source j Boo
Tile available in Inkscape using shift-alt-i on the selected rectangle
Source Firkin
A seamless design of flowers remixed from a jpg on Pixabay by Prawny.
Source Firkin
White little knobs, coming in at 10x10px. Sweet!
Source Amos
Submitted in a cream color, but you know how I like it.
Source Devin Holmes
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Number 2 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
The classic 45-degree diagonal line pattern, done right.
Source Jorick van Hees
Prismatic Groovy Concentric Background 2 No Black
Source GDJ
Just the symbols of the signs of the zodiac distributed in a chequer board-like pattern
Source Firkin
From a drawing in 'Studies for Stories', Jean Ingelow, 1864.
Source Firkin
Alternative colour scheme for the original floral pattern.
Source Firkin
This is a grid, only it’s noisy. You know. Reminds you of those printed grids you draw on.
Source Vectorpile