Real snow that tiles, not easy. This is not perfect, but an attempt.
Source Atle Mo
Same classic 45-degree pattern, dark version.
Source Luke McDonald
Washi (和紙?) is a type of paper made in Japan. Here’s the pattern for you!
Source Carolynne
Light gray version of the Binding pattern that looks a bit like fabric.
Source Newbury
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868
Source Firkin
It’s a hole, in a pattern. On your website. Dig it!
Source Josh Green
Prismatic Curved Diamond Pattern No Background
Source GDJ
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
This is so subtle you need to bring your magnifier!
Source Carlos Valdez
This background has abstract texture with some similarities to wood.
Source V. Hartikainen
Seamless Olive Green Web Background Image
Source V. Hartikainen
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Abstract Tiled Background Extended 10
Source GDJ
From a drawing in 'Uit de geschiedenis der Heilige Stede te Amsterdam', Yohannes Sterck, 1898.
Source Firkin
This one is amazing, truly original. Go use it!
Source Viahorizon
Prismatic Curved Diamond Pattern 2 No Background
Source GDJ
Light and tiny, just the way you like it.
Source Rohit Arun Rao
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
A nice and simple white rotated tile pattern.
Source Another One
Prismatic Curved Diamond Pattern 7 No Background
Source GDJ
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin