Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
Remixed from an image on Pixabay, the original having been uploaded by darkmoon1968.
Source Firkin
Seamless Prismatic Geometric Pattern With Background
Source GDJ
A brown seamless wood texture in a form of stripe pattern. The result has turned out pretty well, in my opinion.
Source V. Hartikainen
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
From a drawing in 'Heroes of North African Discovery', Nancy Meugens, 1894.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Background formed from the iconic plastic construction bricks that gave me endless hours of fun when I was a lad.
Source Firkin
Here's a quite bright pink background pattern for use on websites. It doesn't look like a real fur, but it definitely resembles one.
Source V. Hartikainen
Neat little photography icon pattern.
Source Hossam Elbialy
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
A dark metallic background with a pattern of stamped dots. Here's a dark "metallic" background pattern for you.
Source V. Hartikainen
Same as gray sand but lighter. A sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
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
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
Carbon fiber is never out of fashion, so here is one more style for you.
Source Alfred Lee
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
Light gray paper pattern with small traces of fiber and some dust.
Source Atle Mo
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i
Source Firkin
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
From a drawing in 'Hyde Park from Domesday-Book to date', John Ashton, 1896.
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 web background with texture of aged grid paper.
Source V. Hartikainen