Otrera, mother of Penthesilea
-> Apollodorus, Library e.5.1 - Penthesileia, daughter of Otrere and Ares, accidentally killed Hippolyte and was purified by Priam.
-> Hyginus, Fabulae 30 - Heracles slew Hippolyte, daughter of Mars and Queen Otrera, and took from her the belt of the Amazon Queen.
-> Scholiast on Apollonius of Rhodes, 2.1031a - The island of Aretias: The island was inhabited by Otrera daughter of Ares.
This was a horrendous pain to find, so here's the edition I used. It's at the bottom of page 228 (or 202, according to the book).
-> Hyginus, Fabulae 223 - The Seven Wonders of the World: The temple of Diana at Ephesus which the Amazon Otrera, wife of Mars, made.
-> Apollonius Rhodes, Argonautica 2.285 - Once you pass by [the Mossynoeci] you must put in at a smooth island [...] On it, Otrere and Antiope, queens of the Amazons, built a stone temple to Ares, when they were on campaign.
-> Callimachus, Hymn 3 to Artemis - And to you the Amazons, who are dedicated to war, once by the shore in Ephesus set up an image
beneath an oak trunk, and there Hippo performed the rite for you. They themselves, Oupis, Queen, danced the war dance, first armed with shields, then arranging the broad chorus in a circle. Pipes provided delicate accompaniment with a clear sound, so that their feet might beat in time. [...] Do not flee her yearly dance. For not without tears did Hippo refuse to dance around her altar.
Note from Theoi: The Amazon Queen Hippo was identified with Otrera. Hippo was punished by Artemis for refusing to join the dance at Ephesos.
Note from Susan A. Stephens: Hippo is otherwise unattested as an Amazon (she is an Oceanid in Hes. Th. 351). Possibly it is an alternate name for Hippolyte, the queen of the Amazons, who was the mother of Hippolytus by Theseus. Why Hippo refused to dance is not known.
-> Tzetzes, Ad Lycophronem 997 - Lycophron calls her Otrere because of the active and guileless nature of her mind or because of the fearlessness of her opinion; for she was so just that she often publicly reproached her own husband when he came to court, accusing him of being unjust and unwise. Angered, he killed her with a sword.
-> Hyginus, Fabulae 225 - Otrera, an Amazon, wife of Mars, first founded the temple of Diana at Ephesus.
-> Homer, Iliad 6.171 - So to Lycia [Bellerophon] went, with the gods’ faultless protection, and when he reached Lycia and the Xanthos river, the king of broad Lycia readily paid him honor [...] He slaughtered the Amazons, women well-matched against men.
Note from Theoi: The leader of these Amazons was presumably Queen Otrera who later authors say founded the temple of Artemis in nearby Ephesus.
-> Homer, Iliad 3.185 - The men of Otreus and of Mygdon the godlike at that time encamped along the banks of the Sangarius river. For [Priam] too, being their ally, was then numbered among them that day when the Amazons came, a match for men.
Note from Theoi: Penthesileia's mother Otrera was probably regarded as the leader of this Amazon campaign. Whether her name was known to Homer is debatable - it might have been derived by later authors from the name of the Phrygian king, Otreus, mentioned above.
Also, see here for commentary on whether this was a battle against or with the Phrygians.
There's also "Thracian-born Penthesilea" from Proclus' Chrestomathia which might suggest Otrera is from / has been to Thrace at some point.
