Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
Because I love dark patterns, here is Brushed Alum in a dark coating.
Source Tim Ward
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Remix from a drawing in 'Ostatnie chwile powstania styczniowego', Zygmunt Sulima, 1887.
Source Firkin
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Number 4 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Retro Circles Background 4 No Black
Source GDJ
Prismatic Curved Diamond Pattern 7 No Background
Source GDJ
A bit simplified version. Although it could be edited out to be simpler. Anyway, this time the tiling is converted to a pattern fill -which is using clipping for the tile's edges.
Source Lazur URH
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
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
ZeroCC tileable stone texture, edited from pixabay. CC0
Source Sojan Janso
A seamless pattern formed from miutopia's cakes on a tablecloth.
Source Firkin
Prismatic Groovy Concentric Background No Black
Source GDJ
This one has rusty dark brown texture.
Source V. Hartikainen
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868
Source Firkin
Imagine you zoomed in 1000X on some fabric. But then it turned out to be a skeleton!
Source Angelica
If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper