Redrawn based on a drawing in 'По Сѣверо-Западу Россіи' Konstantin Sluchevsky, 1897.
Source Firkin
A seamless pattern based on a tile that can be achieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A background formed from an image of an old tile on the New York Metropolitan Museum of Art website. To get the base tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Remixed from a raster on Pixabay that was uploaded by ArtsyBee.
Source Firkin
A series of 5 patterns. That’s what the P stands for, if you didn’t guess it.
Source Dima Shiper
Seamless Prismatic Quadrilateral Line Art Pattern No Background
Source GDJ
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
Everyone loves a diamond, right? Make your site sparkle.
Source AJ Troxell
Greyscale version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
This one is super crisp at 2X. Lined paper with some dust and scratches.
Source HQvectors
A seamless web texture with illustration of pale color stains on canvas.
Source V. Hartikainen
A seamless pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
Prismatic Abstract Background Design
Source GDJ
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
Vector version of a JPG that was uploaded to Pixabay by theasad121
Source Firkin
This background image has seamless texture that resembles a surface of gray stone.
Source V. Hartikainen
Prismatic Curved Diamond Pattern 4 No Background
Source GDJ