While Herakles is known for sleeping and impregnating all but one of Thespius' daughters, only forty-eight are listed by name. The only reason that the forty-ninth is known is that his name was Kreon (different from the father of Herakles' first wife).
King Thespius & Queen Megamede (or possibly one of the king's mistresses)
Spouse & Lovers
"... he [Herakles] had Creon" - Apollod. Biblioteca 2.7.8