From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
From a drawing in 'Hubert Montreuil, or the Huguenot and the Dragoon', Francisca Ouvry, 1873.
Source Firkin
This one is amazing, truly original. Go use it!
Source Viahorizon
Has nothing to do with toast, but it’s nice and subtle.
Source Pippin Lee
This background image has seamless texture that resembles a surface of gray stone.
Source V. Hartikainen
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Rounded Squares Grid 3 No Background
Source GDJ
A seamless background pattern with impressed gray dots.
Source V. Hartikainen
Colour version that is close to the original drawing uploaded to Pixabay by pencilparker.
Source Firkin
Detailed but still subtle and quite original. Lovely gray shades.
Source Kim Ruddock
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Colourful background achieved with gradient fills.
Source Firkin