My hello pins* come in three sizes:
*With the exception of the pride hello pins, which are not available in rectangle.
Two paper types are available:
Standard white paper: this means the design is printed on basic copy paper and the colours will be pretty normal.
Recycled paper: badges made using recycled paper with have slightly muted colours as the recycled paper is off white.
All my pins currently have metal backs, but plastic backs are sometimes used if I run into a supply emergency.