Uruguay
- 1856, 80c. green, Ferrer block of 15 - unique
- 1858, 120c. blue, tête-bêche vertical pair - unique
- 1858, 180c Sol de Mayo red error of color - unique
- 1858, 180c. green, in mixed franking with 1860 thick figures 60 c. brown lilac - unique on cover
Read more about this topic: List Of Postage Stamps