| All Series | No on Sale Date | On Sale Date |
| Worlds Unknown | |||||
| number | publicationdate | sortcode | onsaledate | genre | |
| 1 | May 1973 | 56245 | 1973-02-06 | Original work | |
| 2 | July 1973 | 56246 | 1973-04-03 | Original work | |
| 3 | September 1973 | 56247 | 1973-06-05 | Original work | |
| 4 | November 1973 | 56248 | 1973-07-31 | science fiction | Original work |
| 5 | February 1974 | 56249 | 1973-10-30 | horror-suspense; science fiction | Original work |
| 6 | April 1974 | 56250 | 1973-12-18 | horror-suspense; science fiction | Original work |
| 7 | June 1974 | 56251 | 1974-03-05 | fantasy | Original work |
| 8 | August 1974 | 56252 | 1974-04-30 | fantasy | Original work |