A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
From a drawing in 'Cassell's Library of English Literature', Henry Morley, 1883.
Source Firkin
Mostly just mucked about with the colours and made one of the paths in the lead frame opaque. The glass remains transparent.
Source Firkin
From a drawing in 'Studies for Stories', Jean Ingelow, 1864.
Source Firkin
Seamless Green Tile Background
Source V. Hartikainen
Used correctly, this could be nice. Used in a bad way, all hell will break loose.
Source Atle Mo
Not so subtle. These tileable wood patterns are very useful.
Source Elemis
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i
Source Firkin
Inspired by a pattern seen on a public domain image of a very old tile. To get the unit cell, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Abstract Line Art Pattern Background
Source GDJ
Prismatic Groovy Concentric Background
Source GDJ
Zero CC tileable hard cover red book, scanned and made by me. CC0
Source Sojan Janso
Number 2 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A free web background image with a seamless concrete-like texture and an Indian-red color.
Source V. Hartikainen
Heavily remixed from a drawing that was uploaded to Pixabay by ractapopulous
Source Firkin