From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A dark metal plate with an embossed grid pattern and a bit of rust. Here's a dark metal plate texture for use as a tiled background on web pages.
Source V. Hartikainen
More tactile goodness. This time in the form of some rough cloth.
Source Bartosz Kaszubowski
More leather, and this time it’s bigger! You know, in case you need that.
Source Elemis
You just can’t get enough of the fabric patterns, so here is one more for your collection.
Source Krisp Designs
Prismatic Abstract Line Art Pattern Background 2
Source GDJ
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
Background formed from the iconic plastic construction bricks that gave me endless hours of fun when I was a lad.
Source Firkin
A dark gray, sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
A very slick dark rubber grip pattern, sort of like the grip on a camera.
Source Sinisha
Just what the name says, paper fibers. Always good to have.
Source Heliodor jalba
A series of 5 patterns. That’s what the P stands for, if you didn’t guess it.
Source Dima Shiper