From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
A classic dark tile for a bit of vintage darkness.
Source Listvetra
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
Prismatic Groovy Concentric Background 2 No Black
Source GDJ
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
With a name this awesome, how can I go wrong?
Source Nikolay Boltachev
Prismatic Groovy Concentric Background
Source GDJ
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.
Source Firkin
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
A seamless background of warped stripes on paper.
Source V. Hartikainen
More leather, and this time it’s bigger! You know, in case you need that.
Source Elemis
A yellow tiled background... Blurriness, bokeh effect and rectangles pattern in one mix.
Source V. Hartikainen
This is so subtle you need to bring your magnifier!
Source Carlos Valdez
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
Prismatic Groovy Concentric Background No Black
Source GDJ
Love me some light mesh on a Monday. Sharp.
Source Wilmotte Bastien
From a drawing in 'An Old Maid's Love. A Dutch tale told in English', Maarten Maartens, 1891.
Source Firkin
A dark gray, sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Green Background Pattern
Source V. Hartikainen
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin