It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
A pattern drawn in Paint.net and vectorized in Inkscape.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin
Bumps, highlight and shadows – all good things.
Source Badhon Ebrahim
This was formed by distorting an image of a background on Pixabay.
Source Firkin
A dark brown fabric-like background texture with seamless pattern of winding stripes.
Source V. Hartikainen
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Looks like an old rug or a computer chip.
Source Patutin Sergey
Have you wondered about how it feels to be buried alive? Here is the pattern for it.
Source Hendrik Lammers
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
A nice and simple gray stucco material. Great on its own, or as a base for a new pattern.
Source Bartosz Kaszubowski
Could remind you a bit of those squares in Super Mario Bros, yeh?
Source Jeff Wall
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
Prismatic Abstract Line Art Pattern Background
Source GDJ
Continuing the geometric trend, here is one more.
Source Mike Warner
Abstract Arbitrary Geometric Background derived from an image on Pixabay.
Source GDJ
A seamless pattern formed from a tile made from page ornament 22. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin