A seamless pattern formed from a modified version of rwwgub's tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
Derived from a drawing in 'Historiske Afhandlinger', Adolf Jorgensen, 1898.
Source Firkin
A new take on the black linen pattern. Softer this time.
Source Atle Mo
From a drawing in 'Cassell's Library of English Literature', Henry Morley, 1883.
Source Firkin
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
Prismatic Curved Diamond Pattern 4 No Background
Source GDJ
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
It looks like a polished stone surface to me. Download it for free, as always.
Source V. Hartikainen
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
From a drawing in 'A Guide to the Guildhall of the City of London', John Baddeley, 1898.
Source Firkin
Background formed from the original with an emboss effect
Source GDJ
More in the paper realm, this time with fibers.
Source Jorge Fuentes
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
A simple circle. That’s all it takes. This one is even transparent, for those who like that.
Source Saqib
Clean and crisp lines all over the place. Wrap it up with this one.
Source Dax Kieran
The image depicts a seamless pattern of Japanese Edo pattern called "kikkou-matsu" or "亀甲松" meaning " tortoiseshell-pinetree".The real pinetree is like this: https://jp.pinterest.com/pin/500744052301065077/
Source Yamachem