I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
First pattern tailor-made for Retina, with many more to come. All the old ones are upscaled, in case you want to re-download.
Source Atle Mo
f you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
More bright luxury. This is a bit larger than fancy deboss, and with a bit more noise.
Source Viszt Péter
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
Prismatic Snowflakes Pattern 2 No Background
Source GDJ
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin
Might not be super subtle, but quite original in its form.
Source Alex Smith
This background image has seamless texture that resembles a surface of gray stone.
Source V. Hartikainen
A seamless web background with texture of aged grid paper.
Source V. Hartikainen
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A grayscale fabric pattern with vertical lines of stitch holes.
Source V. Hartikainen
Sort of like the Photoshop transparent background, but better!
Source Alex Parker
Number 1 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
Just the symbols of the signs of the zodiac distributed in a chequer board-like pattern
Source Firkin
Looks like an old wall. I guess that’s it then?
Source Viahorizon
This is the remix of "Strawberry Pattern Background" uploaded by "GDJ". Thanks. I realigned strawberries so as to get seamless and changed the BG color.
Source Yamachem