A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
Prismatic Snowflakes Pattern 2 No Background
Source GDJ
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
Looks like an old rug or a computer chip.
Source Patutin Sergey
Adapted from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Number 3 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
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
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
Hexagonal dark 3D pattern. What more can you ask for?
Source Norbert Levajsics