You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
A comeback for you: the popular Escheresque, now in black.
Source Patten
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Did some testing with Repper Pro tonight, and this gray mid-tone pattern came out.
Source Atle Mo
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
Prismatic Floral Pattern 3 Variation 3 No Background
Source GDJ
A beautiful dark wood pattern, superbly tiled.
Source Omar Alvarado
Floral patterns might not be the hottest thing right now, but you never know when you need it!
Source Lauren
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
Tweed is back in style – you heard it here first. Also, the @2X version here is great!
Source Simon Leo
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'A Rolling Stone. A tale of wrongs and revenge', John Hartley, 1878.
Source Firkin
This is a seamless pattern which is derived from a flower petal image.
Source Yamachem
Dark, lines, noise, tactile. You get the drift.
Source Anatoli Nicolae
This is indeed a bit strange, but here’s to the crazy ones!
Source Christopher Buecheler
A seamless pattern of dark bricks. Maybe it's not very realistic, but it looks good in my opinion.
Source V. Hartikainen
Super simple but very nice indeed. Gray with vertical stripes.
Source Merrin Macleod
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin