From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel
From a drawing in 'Picturesque New Guinea', J Lindt, 1887.
Source Firkin
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
New paper pattern with a slightly organic feel to it, using some thin threads.
Source Atle Mo
Drawn in Paint.net and vectorised in Vector Magic
Source Firkin
A pale orange background pattern with glossy groove stripes.
Source V. Hartikainen
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
This seamless background image should look nice on websites. It has a dark blue gray texture with vertical stripes, it tiles seamlessly and, like all of the background images here, it's free. So, if you like it, take it!
Source V. Hartikainen
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
This one is amazing, truly original. Go use it!
Source Viahorizon
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous