From a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
Zero CC Mossy stone tileable texture, photographed and made by me. CC0
Source Sojan Janso
A floral background formed from numerous clones of flower 117.
Source Firkin
Formed by distorting a JPG from PublicDomainPictures
Source Firkin
A bit like smudged paint or some sort of steel, here is scribble light.
Source Tegan Male
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
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
Real snow that tiles, not easy. This is not perfect, but an attempt.
Source Atle Mo
Did anyone say The Hoff? This pattern is in no way related to Baywatch.
Source Josh Green
Prismatic Geometric Pattern Variation 2 With Background
Source GDJ
One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
You could get a bit dizzy from this one, but it might come in handy.
Source Dertig Media
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Hexagonal dark 3D pattern. What more can you ask for?
Source Norbert Levajsics
Dark blue concrete wall with some small dust spots.
Source Atle Mo
Number 4 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Tiny circle waves, almost like the ocean.
Source Sagive
A criss-cross pattern similar to one I saw mown into a sports field.
Source Firkin
The image depicts a seamless pattern of a Japanese family crest called "chidori" in Japanese .A chidori in Japanese means a plover in English.
Source Yamachem
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin