The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
I love these crisp, tiny, super subtle patterns.
Source Badhon Ebrahim
Light honeycomb pattern made up of the classic hexagon shape.
Source Federica Pelzel
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
Not the most creative name, but it’s a good all-purpose light background.
Source Dmitry
Dark, lines, noise, tactile. You get the drift.
Source Anatoli Nicolae
Used in small doses, this could be a nice subtle pattern. Used on a large surface, it’s dirty!
Source Paul Reulat
Could be paper, could be a Polaroid frame – up to you!
Source Chaos
Number 4 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
Prismatic Floral Pattern 3 Variation 3 No Background
Source GDJ
It’s like Shine Dotted’s sister, only rotated 45 degrees.
Source mediumidee
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A seamless pattern formed from background pattern 102
Source Firkin
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
Abstract Tiled Background Extended 11
Source GDJ
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
A fun-looking elastoplast/band-aid pattern. A hint of orange tone in this one.
Source Josh Green
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
Inspired by a 1930s wallpaper pattern I saw on TV.
Source Firkin
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin