| Issuer | Date | Desc | State | ||
| - | no image | Gabon | 1/31/1990 | empty sheet (#21851) | incomplete |
| - | no image | Gabon | 2/14/1990 | sheet of 4 types | all added |
| - | no image | Gabon | 6/8/1990 | empty sheet (#21853) | incomplete |
| - | no image | Gabon | 9/12/1990 | empty sheet (#21854) | incomplete |