To get the tile this is based on select the rectangle in Inkscape and use 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
Same as the black version, but now in shades of gray. Very subtle and fine grained.
Source Atle Mo
There are quite a few grid patterns, but this one is a super tiny grid with some dust for good measure.
Source Dominik Kiss
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
This background pattern contains a seamless texture of bark. It's not very realistic, but I think it looks quite nice.
Source V. Hartikainen
I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
A hint of orange color, and some crossed and embossed lines.
Source Adam Anlauf
Lovely pattern with splattered vintage speckles.
Source David Pomfret
More in the paper realm, this time with fibers.
Source Jorge Fuentes
Used in small doses, this could be a nice subtle pattern. Used on a large surface, it’s dirty!
Source Paul Reulat