A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
Prismatic Abstract Geometric Background 5
Source GDJ
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin
Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Seamless Light Background Texture.
Source V. Hartikainen
So tiny, just 7 by 7 pixels – but still so sexy. Ah yes.
Source Dmitriy Prodchenko
Here's a dark background pattern that contains a steel grid pattern as a texture. Use it as a website background or for other purposes. It's free!
Source V. Hartikainen
With a name like this, it has to be hot. Diagonal lines in light shades.
Source Isaac
Stefan is hard at work, this time with a funky pattern of squares.
Source Stefan Aleksić
Not so subtle. These tileable wood patterns are very useful.
Source Elemis
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
Prismatic Rounded Squares Grid 3 No Background
Source GDJ
Dark pattern with some nice diagonal stitched lines crossing over.
Source Ashton
Hey, you never know when you’ll need a bird pattern, right?
Source Pete Fecteau
A very slick dark rubber grip pattern, sort of like the grip on a camera.
Source Sinisha