This is the remix of an OCAL clipart called "Rain on Window" uploaded by "pagarmidna".Thanks.This is a seamless pattern of raindrops.
Source Yamachem
The image depicts a Japanese Edo pattern called "kanoko or 鹿の子" meaning "fawn" which has a fur with small white spots.
Source Yamachem
This is the remix of an Openclipart clipart called "Maze" uploaded by "any_ono_mous".Thanks.This is a seamless pattern of a maze.
Source Yamachem
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A dark gray, sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
No idea what Nistri means, but it’s a crisp little pattern nonetheless.
Source Markus Reiter
A comeback for you: the popular Escheresque, now in black.
Source Patten
Derived from a PNG that was uploaded to Pixabay by nutkitten
Source Firkin
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
The tile can be had by using shift+alt+i on the selected rectangle in Inkscape
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
The image depicts polka dot seamless pattern.
Source Yamachem
More Japanese-inspired patterns, Gold Scales this time.
Source Josh Green
ZeroCC tileable beechwood wood texture, generated in Neo Texture Edit by me. CC0
Source Sojan Janso
This is sort of fresh, but still feels a bit old school.
Source Martuchox