The base gradient edited so now more details are rendered.
Source Lazur URH
Prismatic Curved Diamond Pattern 6 No Background
Source GDJ
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
This pack of filters can help you adding a blocky overlay to objects. May come handy at drawing blocks of stone.
Source Lazur URH
A seamless pattern drawn originally in Paint.net by distorting a slice of background pattern 116 and copying the resulting triangle numerous times.
Source Firkin
Same as the black version, but now in shades of gray. Very subtle and fine grained.
Source Atle Mo
Inspired by a 1930s wallpaper pattern I saw on TV.
Source Firkin
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
Wild Oliva or Oliva Wilde? Darker than the others, sort of a medium dark pattern.
Source Badhon Ebrahim
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin
This is a remix of "flower seamless pattern".I rotated the original image by 90 degrees.This is a seamless pattern of flowers.These horizontal wavy lines are one of Edo patterns which is called "tatewaku or tachiwaku or 立湧" that represents uprising steam or vapor.
Source Yamachem
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
Paper pattern with small dust particles and 45-degree strokes.
Source Atle Mo
Because I love dark patterns, here is Brushed Alum in a dark coating.
Source Tim Ward
Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
Sounds French. Some 3D square diagonals, that’s all you need to know.
Source Graphiste
The tile can be had by selecting the rectangle in Inkscape and using shift+alt+i. Remixed from a drawing in 'Flowers of Song', Frederick Weatherly, 1895.
Source Firkin
Alternative colour scheme for the original floral pattern.
Source Firkin
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
This one is something special. I’d call it a flat pattern, too. Very well done, sir!
Source GetDiscount
Prismatic Snowflakes Pattern 3 No Background
Source GDJ