The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Not so subtle. These tileable wood patterns are very useful.
Source Elemis
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Paper model of a tetrahedron. Modelo de papel de um tetraedro.
Source laobc
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
Derived from a PNG that was uploaded to Pixabay by nutkitten
Source Firkin
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
A seamless dark leather-like background texture with diagonal lines that look like stitches.
Source V. Hartikainen
Remixed from an image that was uploaded to Pixabay by Pixeline
Source Firkin
Abstract Stars Geometric Pattern Prismatic No Background
Source GDJ
Because I love dark patterns, here is Brushed Alum in a dark coating.
Source Tim Ward
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Abstract Stars Geometric Pattern Prismatic No Background
Source GDJ
Prismatic Groovy Concentric Background 2
Source GDJ
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Gold Triangular Seamless Pattern No Background
Source GDJ
Plywood Web Background background image for use in web design.
Source V. Hartikainen