As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
A seamless pattern formed from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Kaleidoscope Prismatic Abstract No Background
Source GDJ
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Similar to original, but without gaps in between the arrows. This seamless pattern was created from a rectangular tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
More Japanese-inspired patterns, Gold Scales this time.
Source Josh Green
Not so subtle. These tileable wood patterns are very useful.
Source Elemis
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Did anyone say The Hoff? This pattern is in no way related to Baywatch.
Source Josh Green
A seamless pattern formed from a tile made from ornament 22. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
Snap! It’s a pattern, and it’s not grayscale! Of course you can always change the color in Photoshop.
Source Atle Mo
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857
Source Firkin
Remixed from a drawing in 'An Index to Deering's Nottinghamia Vetus et Nova', Rupert Chicken, 1899. The unit tile can be had by selecting the rectangle in Inkscape and using shift-alt-i
Source Firkin
Derived from a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
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
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
Scanned some rice paper and tiled it up for you. Enjoy.
Source Atle Mo
Zero CC tileable bark texture, photographed and made by me. CC0
Source Sojan Janso
Light gray version of the Binding pattern that looks a bit like fabric.
Source Newbury
Alternative colour scheme for the original floral pattern.
Source Firkin
Psychedelic Geometric Background No Black
Source GDJ