Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
A large (588x375px) sand-colored pattern for your ever-growing collection. Shrink at will.
Source Alex Tapein
I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel
Seamless Prismatic Geometric Pattern With Background
Source GDJ
A series of 5 patterns. That’s what the P stands for, if you didn’t guess it.
Source Dima Shiper
This one is amazing, truly original. Go use it!
Source Viahorizon
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Smooth Polaroid pattern with a light blue tint.
Source Daniel Beaton
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A textured blue background pattern with vertical stripes.
Source V. Hartikainen
No idea what Nistri means, but it’s a crisp little pattern nonetheless.
Source Markus Reiter
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin