Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Remixed from a drawing in 'Analecta Eboracensia', Thomas Widdrington, 1897.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
This white background pattern has a seamless grunge style texture. Here's a white grunge style background pattern. Use it as a tiled background image on web sites or for other purposes.
Source V. Hartikainen
Lovely light gray floral motif with some subtle shades.
Source GraphicsWall
Formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
I love these crisp, tiny, super subtle patterns.
Source Badhon Ebrahim
Kaleidoscope Prismatic Abstract No Background
Source GDJ
Used in small doses, this could be a nice subtle pattern. Used on a large surface, it’s dirty!
Source Paul Reulat
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
Super simple but very nice indeed. Gray with vertical stripes.
Source Merrin Macleod
Remixed from a drawing in 'Works. Popular edition', John Ruskin, 1886.
Source Firkin
Hey, you never know when you’ll need a bird pattern, right?
Source Pete Fecteau
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
Dark wooden pattern, given the subtle treatment. based on texture from Cloaks. https://cloaks.deviantart.com
Source Atle Mo
Sharp pixel pattern looking like some sort of fabric.
Source Dmitry
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin