Ariadne and the Battle of the Brothers
In one source, Perseus is supposed to have used Medusa's power at least once after Seriphos.
In the last third of the second-last book of his epic, the Dionysiaca, the Egyptian writer Nonnus narrates the conclusion of a tour of Greece taken by the wine-god Dionysus. At the time, Dionysus' half-brother Perseus rules over the region of Argolis. Their stepmother Hera, who passionately hates Dionysus, is the queen of the gods and is also the patron deity of Argos, one of the major cities of Argolis. Meanwhile Dionysus has recently come from the island of Naxos, where he's recently made the Cretan princess Ariadne his wife.
Upon the wine-god's arrival in Argos, together with his new bride and their army of drunken revellers, the city's dwellers (who are apparently aware of Hera's sentiments towards Dionysus), turn them away from their home, afraid that their goddess will be offended if they receive her enemy stepson. At this, Dionysus induces madness in the city's women so that they start to butcher their own children.
Hera then disguises herself as the prophet Melampus, a relative of Perseus who also rules over Argos. In this form she rouses Perseus to defend her city against Dionysus' attack. At this point, according to Nonnus, Perseus is still in possession of both Medusa's severed head and the winged sandals which aided him in his mission to acquire the head. He uses these in the counter-attack upon his wine-god half-brother.
Ariadne is armed for battle and fights in the ranks of her bridegroom's troops of Bacchantes (a group of Dionysus' women who each seem to be one part wild dancer, one part fierce warrior, one part drunkard, and all berserk). Dionysus appears to have anticipated Medusa's head as a factor in this fight, for he has prepared himself to ward off the Gorgon's power by the use of a diamond. It is unclear whether he has surmounted his thyrsus (his signature pine-cone wand) with the gem; is wearing the diamond on a necklace, or if it is attached to his face like a bindi; or if he is simply carrying it in his other hand, perhaps in front of his eyes. As Nonnus says in Book 47, Lines 590-593:
The thyrsus was held up in his hand, and to defend his face he carried
a diamond, the gem made stone in the showers of Zeus which protects
against the stony glare of Medusa, that the baleful light of that
destroying face may do him no harm.
Ariadne, who is not similarly shielded against the Gorgon-head, is unceremoniously turned to stone as Perseus goes up against the Bacchantes. In his rage over this, Dionysus is ready to destroy Argos, burn Mycenae (another city of Argolis, this one built by Perseus himself) to the ground, and kill all the land's inhabitants. However, another half-brother of his, the messenger-god Hermes, appears behind him and convinces him to cease fighting, explaining that Hera, who is involved in the battle, might have the strength to defeat him.
Just as Dionysus' own mortal mother Semele became a goddess of Olympus after she died, says Hermes to the wine-god, so would Ariadne join his company in the home of the immortals as well. With Hermes' help, Dionysus and Perseus afterwards become friends while the real Melampus establishes the cult of Dionysus in Argolis. The wine-god then moves on from there to Thrace to conclude his adventures in the final book of the Dionysiaca.
Attempting to Explain Athena Itonia and Iodama
There are, besides, instances of petrification (or, if you like, petrifaction) stories occurring while Athena is in possession of the Gorgon-head.
First there is the weird story of Iodama (or Iodameia), from the neighbourhood of Coroneia and Alalcomenae in Boeotia, related by Pausanias, which you have noted in your own Answer to the Question. I call it weird because there is no context given for the circumstances of this petrification, considering that Iodama is a priestess of Athena. Why does the goddess do this to her?
And also it is narrated ambiguously enough to render it unclear whether we are to understand that in Athena Itonia's temple there is a lifelike statue of a woman which is supposed to be the surprised Iodama, now venerated as somewhat of a minor divinity. Such a detail is the sort of thing with which Pausanias would usually not fail to engage us.
The only attempt at an explanation of this that I have come across is in Robert Graves' book The Greek Myths, in which he presents two ideas regarding the matter. His first suggestion is that this is a different version of the tale in which Athena accidentally kills her own sister, or foster-sister, Pallas daughter of Triton.
The way Graves tells it, Athena is called Itonia here as a patronymic, because Itonus is her father, which makes her Iodama's sister. The other suggestion is that Iodama was trespassing into Athena Itonia's precinct by venturing into it in the night-time, where, so it would seem, Athena was not expecting to meet her.
Iodama, probably meaning 'heifer calf of Io', will have been an
antique stone image of the Moon-goddess... and the story of her
petrification is a warning to inquisitive girls against violating the
Or at least that is what Graves would like to believe about that (p. 47). Incidentally, there is a much more explicit tradition regarding an alternate paternity of Athena from the neighbouring village of Alalcomenae, which was named after an Autochthon (a man born directly from the ground) called Alalcomenes. The villagers here said that Alalcomenes was the father of Athena or at least that he and his wife Athenaïs raised the goddess.
The Introduction to Athena's Father Pallas
In yet one more alternate Athena origin story, mentioned by the Roman writer Cicero, as well as by Clement of Alexandria, there were five different versions of the goddess. One of these was the daughter of an Oceanid named Titanis (meaning simply "female Titan") while her father was called Pallas. It is ambiguous whether this Pallas is supposed to have been the winged Titan who married the river Styx and became by her the father of Victory (Nike), Jealousy (Zelos), Might (Kratos) and Violence (Bia), or if the Pallas in view is a winged Giant among those who waged war against the gods and paid for it with their lives.
At any rate, in this version, Athena's own father Pallas tried to rape her and was killed for this presumption, whereupon the goddess then flayed his leathery corpse, which was somewhat like that of a goat, and used his skin as casing for her breastplate or shield, the Aegis, whose name is connected with the Greek word for goat. She placed his wings on her feet and used them to fly like Hermes. If the Pallas envisioned here is the Titan, then Athena probably represents warcraft, to match up with her siblings, the four winged Titans of conquest, zeal, power and force.
Going back to the petrification issue, for the Roman version of the death of the Giant Pallas, the poet Claudian paints quite the scene in his Gigantomachia, "Giants' War." During the Giants' attack on the stronghold of the gods, four Giants rushed against Minerva, the Roman Athena. She was wearing Medusa's head on her breastplate, and when the first Giant, Pallas, charged against her, Minerva "needed not to use a spear" because just the sight of the breastplate turned Pallas to stone.
Bewildered by this, Pallas' brother, another Giant named Damastor, scrambled for a weapon to use in the fight. Failing to think of anything better, he grabbed the petrified corpse of Pallas and launched it as a missile upon the gods. Presumably this did not end well for him, though Claudian does not say, instead skipping forward to another Giant named Echion:
Then Echion, marveling, all ignorant, at his brother’s death, even as
he seeks to assail the author of the deed, turned his gaze upon you,
goddess, whom alone no man may see twice. Beaten audacity well
deserved its punishment and in death he learned to know the goddess.
That is also vague but implies that Echion, like Pallas, was turned to stone by Medusa's head.
The fourth and final attacker of Minerva was the Giant Palleneus (merely another version of Pallas?), who flailed with a sword, wildly, at the goddess. When he had drawn close enough Minerva struck him with her own sword. At the same time his lower half, which was composed of giant snakes, looked at the Gorgon's head and froze into stone, "so that one part of the body was killed by a weapon and another part by a mere look." (See Lines 91-113.)