Another fairly simple design drawn in Paint.net and vectorized in Inkscape.
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
Prismatic Groovy Concentric Background 2
Source GDJ
Zero CC tileable brick texture, photographed and made by me. CC0
Source Sojan Janso
A bit simplified version. Although it could be edited out to be simpler. Anyway, this time the tiling is converted to a pattern fill -which is using clipping for the tile's edges.
Source Lazur URH
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A simple circle. That’s all it takes. This one is even transparent, for those who like that.
Source Saqib
A seamless pattern the starting point for which was a 'colour modulo' texture in Paint.net.
Source Firkin
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
Here's a camo print with more tan and less green, such as might be used in a desert scenario. This is tileable, so it can be used as a wallpaper or background.
Source Eady
This one could be the shirt of a golf player. Angled lines in different thicknesses.
Source Olivier Pineda
Luxurious looking pattern (for a T-shirt maybe?) with a hint of green.
Source Simon Meek
Remixed from a drawing in 'A Girl in Ten Thousand', Elizabeth Meade, 1896.
Source Firkin
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
This is indeed a bit strange, but here’s to the crazy ones!
Source Christopher Buecheler
Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
Traced from a drawing in 'Household Stories from the Collection of the Brothers Grimm', Wilhelm Carl Grimm , 1882.
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin