Coming in at 666x666px, this is an evil big pattern, but nice and soft at the same time.
Source Atle Mo
A dark gray, sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
Remixed from a drawing in 'The March of Loyalty', Letitia MacClintock, 1884.
Source Firkin
An emulated “transparent” background pattern, like that of all kinds of computer graphics software.
Source AdamStanislav
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
Real snow that tiles, not easy. This is not perfect, but an attempt.
Source Atle Mo
Derived from a drawing in 'The Murmur of the Shells', Samuel Cowen, 1879.
Source Firkin
Prismatic Hypnotic Pattern No Background
Source GDJ
This seamless background image should look nice on websites. It has a dark blue gray texture with vertical stripes, it tiles seamlessly and, like all of the background images here, it's free. So, if you like it, take it!
Source V. Hartikainen
A free seamless background texture of "timber wall" (colored in dark brown).
Source V. Hartikainen
One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
From a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
ZeroCC tileable mossy (lichen) stone texture, edited from pixabay. CC0
Source Sojan Janso
Prismatic Abstract Geometric Background 3
Source GDJ
Real snow that tiles, not easy. This is not perfect, but an attempt.
Source Atle Mo
You know, tiny and sharp. I’m sure you’ll find a use for it.
Source Atle Mo
Use shift+alt+i on the selected rectangle in Inkscape to get the tile this is based on
Source Firkin