From a drawing in 'Kingsdene', Maria Fetherstonehaugh, 1878.
Source Firkin
An abstract pale yellow paper-like background with stains colored in yellow and green.
Source V. Hartikainen
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Light gray grunge wall with a nice texture overlay.
Source Adam Anlauf
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
This one is something special. I’d call it a flat pattern, too. Very well done, sir!
Source GetDiscount
A very dark spotted twinkle pattern for your twinkle needs.
Source Badhon Ebrahim
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Tiny circle waves, almost like the ocean.
Source Sagive
Looks like an old rug or a computer chip.
Source Patutin Sergey
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
By popular request, an outline version of the pentagon pattern.
Source Atle Mo
Classic vertical lines, in all its subtlety.
Source Cody L
Prismatic Polka Dots 3 No Background
Source GDJ
Used correctly, this could be nice. Used in a bad way, all hell will break loose.
Source Atle Mo