A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.
Source Atle Mo
Remixed from an image that was uploaded to Pixabay by KirstenStar
Source Firkin
The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
A seamless dark leather-like background texture with diagonal lines that look like stitches.
Source V. Hartikainen
A pattern formed from repeated instances of corner decoration 8. To get the basic tile select the rectangle in Inkscape and use shift+alt+i
Source Firkin
Not sure if this is related to the Nami you get in Google image search, but hey, it’s nice!
Source Dertig Media
We have some linen patterns here, but none that are stressed. Until now.
Source Jordan Pittman
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Sounds like something from World of Warcraft. Has to be good.
Source Tony Kinard
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Groovy Concentric Background 5 No Black
Source GDJ
Prismatic Groovy Concentric Background 4
Source GDJ
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
Nothing like a clean set of bed sheets, huh?
Source Badhon Ebrahim
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
Prismatic Rounded Squares Grid 3 No Background
Source GDJ
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 texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Sharp pixel pattern looking like some sort of fabric.
Source Dmitry