This one looks like a cork panel. Feel free to use it as a tiled background on your blog or website.
Source V. Hartikainen
Inspired by a drawing in 'Kulturgeschichte', Freidrich Hellwald, 1896.
Source Firkin
Prismatic Geometric Pattern Background
Source GDJ
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Prismatic Snowflakes Pattern 2 No Background
Source GDJ
A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.
Source Atle Mo
Bit of a strange name on this one, but still nice. Tiny gray square things.
Source Carlos Valdez
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
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