Lovely pattern with splattered vintage speckles.
Source David Pomfret
Psychedelic Geometric Background No Black
Source GDJ
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Prismatic Geometric Tessellation Pattern 3 No Background
Source GDJ
Here's a new paper-like background for free use on personal and commercial projects (this applies to all background patterns here).
Source V. Hartikainen
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A floral background formed from numerous clones of flower 117.
Source Firkin