From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A seamless pattern formed from background pattern 102
Source Firkin
Carbon fiber is never out of fashion, so here is one more style for you.
Source Alfred Lee
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
A dark gray, sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
This one is super crisp at 2X. Lined paper with some dust and scratches.
Source HQvectors
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
A cute x, if you need that sort of thing.
Source Juan Scrocchi
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Orange-red pattern for tiled backgrounds.
Source V. Hartikainen
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Derived from a PNG that was uploaded to Pixabay by nutkitten
Source Firkin
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
ZeroCC tileable stone texture, edited from pixabay. CC0
Source Sojan Janso
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
From a drawing in 'Two Women in the Klondike', Mary Hitchcock, 1899.
Source Firkin
Brushed aluminum, in a bright gray version. Lovely 2X as well.
Source Andre Schouten