The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
You know I’m a sucker for these. Well-crafted paper pattern.
Source Mihaela Hinayon
Zero CC tileable hard cover cells, skin like, book texture. 4K, Scanned and made by me CC0
Source Sojan Janso
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
More in the paper realm, this time with fibers.
Source Jorge Fuentes
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Zero CC Mossy stone tileable texture, photographed and made by me. CC0
Source Sojan Janso
An abstract texture of water. It's not perfect, but will do. You may download if you like it.
Source V. Hartikainen
The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
Prismatic Polyskelion Pattern No Background
Source GDJ
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Original minus the background
Source Firkin
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
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
Everyone needs some stardust. Sprinkle it on your next project.
Source Atle Mo
Lovely pattern with some good-looking non-random noise lines.
Source Zucx
Vertical lines with a bumpy, yet crisp, feel to it.
Source Raasa
Colour version that is close to the original drawing uploaded to Pixabay by pencilparker.
Source Firkin
Kaleidoscope Prismatic Abstract No Background
Source GDJ