| Issuer | Date | Desc | State | ||
| - | no image | Tonga | 7/11/1988 | 200th Anniversary of Colonization of Australia, sheet of 12 types | all added |
| - | no image | Tonga | 9/9/1988 | Sport Aid '88, sheet of 2 types | incomplete |
| - | no image | Tonga | 10/20/1988 | empty sheet (#19855) | incomplete |