| Issuer | Date | Desc | State | ||
| - | no image | Niger | 1/15/1991 | sheet of 1 type | |
| - | no image | Niger | 3/19/1991 | 500th Anniversary of the Discovery of America, sheet of 1 type | |
| - | no image | Niger | 7/15/1991 | empty sheet (#35690) | incomplete |
| - | no image | Niger | 7/15/1991 | empty sheet (#35691) | incomplete |
| - | no image | Niger | 7/15/1991 | empty sheet (#35692) | incomplete |
| - | no image | Niger | 7/15/1991 | empty sheet (#35693) | incomplete |
| - | no image | Niger | 7/15/1991 | empty sheet (#35694) | incomplete |
| - | no image | Niger | 7/15/1991 | empty sheet (#35695) | incomplete |
| - | no image | Niger | 7/15/1991 | empty sheet (#35696) | incomplete |
| - | no image | Niger | 10/15/1991 | empty sheet (#35697) | incomplete |
| - | no image | Niger | 10/15/1991 | empty sheet (#35698) | incomplete |
| - | no image | Niger | 10/15/1991 | empty sheet (#35699) | incomplete |
| - | no image | Niger | 10/15/1991 | empty sheet (#35700) | incomplete |
| - | no image | Niger | 10/15/1991 | empty sheet (#35701) | incomplete |
| - | no image | Niger | 10/15/1991 | empty sheet (#35702) | incomplete |
| - | no image | Niger | 10/15/1991 | empty sheet (#35703) | incomplete |