Misconceptions on Gnostic beliefs

It is common to find many matter-of-fact statements on Gnostic belief via Google all over the internet nowdays. They are often wrong though. For instance, we find the idea that Gnostics believed the Jewish God was evil and they were anti-Semites. This of course is absurd as anti-Semitism did not exist for one thing, and the idea that YHWH was evil is an interpretation based on how these people chose to read polemics. It is also conjecture on the part of Irenaeus to say that Valentinus' Christ is Simon Magus himself. These ideas are absurd because they ignore the succession of these Gnostic groups as given by the church fathers, as well as ignoring the actual beliefs of each leader and group individually.

Simon Magus is said to have tried to buy the holy spirit's power to pass it on via the laying on of hands from Peter. Enemies of Paul were said to have charged for the teaching. Simon is also said to have taught that he was Christ. He said he was the son in Jerusalem and was crucified but he escaped or lived and came to Samaria and Rome as the Father and Paraclete. Thus, he claimed he was the Father, Son, and Holy spirit which we find later in Monarchian belief, Sabellian belief, or what Tertullian derides as Patripassianism. We also find the idea that Simon of Cyrene was crucified in place of Jesus in the beliefs of Basilides. The belows is a genealogical table of heresies from Simon to Basilides.

1. Simon Magus (Jerusalem, Samaria)- taught he was Christ and could not be held by death and that his disciples would live forever by eating his flesh and blood. Derided the God of the Jews as an angel and demeaned the law and prophets. There was no carnal resurrection because he came back as a phantom.
2. Menander (Samaria)- disciple of Simon Magus, taught that he was the new Christ in succession. Baptized people in his own name.
3. Saturninus (Antioch, Syria)- disciple of Menander who taught that he was the new Christ.
4. Basilides (Alexandria, Egypt)- schismatic of the Simonian sect, disciple of Menander and opponent of Saturninus of Antioch. The God of the Jews was an angel (may or may not have been Simon's innovation rather than Basilides'). He spoke of 365 heavens. He is the first to teach that Simon of Cyrene was crucified in place of Jesus rather than Simon Magus being the Christ. He opposed martyrdom. He followed all of Simon's doctrines and either added his own or was more true to Simon than Saturninus. Innovated the idea of Abraxas.
5. Ignatius (Antioch, Syria)- Opposed docetic claims but spoke ex cathedra and claimed a sort of Christ within himself teaching about the bishop of Syria.
6. Isidore (Alexandria, Egypt)- Son and pupil of Basilides. Last keeper of Basilidian doctrine.
7. Cerinthus (Ephesus, Asia)- An heir to the teaching of Basilides or Saturninus. Taught the creation of the cosmos by angels. God of the Jews as an angel. Law given by angels. He kept the Mosaic law. He seems to be a fake-Jew opponent of Ignatius who is taking some ideas of Basilides and merging them with a Hellenic Judaism.

The above is basically what we know from patristics. The rest is all speculation.