This one has rusty dark brown texture.
Source V. Hartikainen
Sharp pixel pattern looking like some sort of fabric.
Source Dmitry
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Detailed but still subtle and quite original. Lovely gray shades.
Source Kim Ruddock
Prismatic Groovy Concentric Background 2 No Black
Source GDJ
Derived from an image that was uploaded to Pixabay by Kaz
Source Firkin
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
Remixed from an image that was uploaded to Pixabay by CatherineClennan
Source Firkin
Prismatic Polka Dots Mark II 2 No Background
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Prismatic Snowflakes Pattern 3 No Background
Source GDJ
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
A seamless textured paper for backgrounds. Colored in pale orange hues.
Source V. Hartikainen
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Seamless pattern inspired by a drawing on Pixabay. To get the tile this is formed from, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
White circles connecting on a light gray background.
Source Mark Collins
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
From a drawing in 'Hubert Montreuil, or the Huguenot and the Dragoon', Francisca Ouvry, 1873.
Source Firkin
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
Seamless Light Background Texture.
Source V. Hartikainen
Used in small doses, this could be a nice subtle pattern. Used on a large surface, it’s dirty!
Source Paul Reulat