People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley
A seamless texture of worn out "cardboard".
Source V. Hartikainen
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A green background pattern with warped vertical stripes and a grunge look.
Source V. Hartikainen
Inspired by a drawing seen in 'City of Liverpool', James Picton, 1883.
Source Firkin
Number 5 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Luxury pattern, looking like it came right out of Paris.
Source Daniel Beaton
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
Wild Oliva or Oliva Wilde? Darker than the others, sort of a medium dark pattern.
Source Badhon Ebrahim
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
The image depicts an edo-era pattern called "same-komon" or "鮫小紋"which looks like a shark skin.The "same" in Japanese means shark in English.
Source Yamachem
Floral patterns might not be the hottest thing right now, but you never know when you need it!
Source Lauren
This one could be the shirt of a golf player. Angled lines in different thicknesses.
Source Olivier Pineda
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
All good things come in threes, so I give you the third in my little concrete wall series.
Source Atle Mo
This ladies and gentlemen, is texturetastic! Love it.
Source Adam Pickering
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
This is lovely, just the right amount of subtle noise, lines and textures.
Source Richard Tabor
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Redrawn based on a drawing in 'По Сѣверо-Западу Россіи' Konstantin Sluchevsky, 1897.
Source Firkin