Real snow that tiles, not easy. This is not perfect, but an attempt.
Source Atle Mo
A seamless pattern the starting point for which was a 'colour modulo' texture in Paint.net.
Source Firkin
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Prismatic Groovy Concentric Background
Source GDJ
You know you can’t get enough of these linen-fabric-y patterns.
Source James Basoo
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
Sharp pixel pattern looking like some sort of fabric.
Source Dmitry
A seamless background tile of aged paper with shabby look.
Source V. Hartikainen
Derived from a PNG that was uploaded to Pixabay by nutkitten
Source Firkin
Colorful Floral Background No Black
Source GDJ
Dead simple but beautiful horizontal line pattern.
Source Fabian Schultz
Dark, square, clean and tidy. What more can you ask for?
Source Jaromír Kavan
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Prismatic Floral Pattern 3 Variation 3 No Background
Source GDJ
Number 5 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
There are quite a few grid patterns, but this one is a super tiny grid with some dust for good measure.
Source Dominik Kiss
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
A seamless background pattern with a texture of wood planks. This wood background pattern has vertically arranged planks. You may try to rotate it 90°, to see how it will look like when the wood planks are arranged horizontally.
Source V. Hartikainen
This is a remix of "flower seamless pattern".I rotated the original image by 90 degrees.This is a seamless pattern of flowers.These horizontal wavy lines are one of Edo patterns which is called "tatewaku or tachiwaku or 立湧" that represents uprising steam or vapor.
Source Yamachem
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
Tiny circle waves, almost like the ocean.
Source Sagive