There are many other people to blame.
1. The Putnams. Mrs. Putnam was fixated on assigning blame for the death of her children. She had already resorted to witchcraft to find out who "murdered" her children, so was quick to jump on the accusation band-wagon. Thomas Putnam, we learn in act three, had been "prompting" his daughter to cry out against people whose land he wanted to take when they were imprisoned.
2. Reverend Parris. Quick to blame those who didn't like him, and to try to win favor in the town by being a lackey to the judges, Parris often sided against the townspeople, asking incriminating questions and giving the judges prejudiced backstories on people brough into the courts. He also conveniently left out the fact that his own niece had been caught dancing and concocting spells in the forest; desparate to protect his reputation, he didn't tell this information.
3. Danforth and Hathorne. These judges often rejected logical fact, devised tricky scenarios and questioning, and refused to hear testimony that would prove the innocence of so many that were accused. Once it became clear the accusations were false, they clung to their pride, refusing to recant convictions, so that their reputations wouldn't be foiled.
Those are just a few people that contributed, and were all too happy to jump in and ride the wave of accusations. I hope that helped; good luck!
Yes, Abigail is largely to blame here, but again, other characters contributed to the witchcraft hysteria of Salem. Reverends Hale and Parris (at least in the first part of the play) feed the fires of the witchcraft rumors, as do the Putnams, who are bitter because of their seven dead babies. The judges and magistrates in this story are also co-conspirators through their subjective application of religious law. The only one who seems to be speaking with any degree of common sense is John Proctor, and for doing so, he is hanged. There is a great deal of deception and back-biting that transpires throughout the play itself, and it is this lying and hypocrisy that become greater sins than witchcraft by the play's end.
Although Abigail Williams is very much to blame for the witch trials, she is certainly not the only one who is responsible.
After all, she is just a teenaged girl. If she had brought these accusations forward and the adults in the community had not believed, nothing would have happened. So, to me, the real blame lies with people like Parris and Hale and Danforth. They are the ones who take the accusations seriously (for various reasons).
I would also blame the people like the Putnams who have power and use the trials to get more. And I would blame the society as a whole for being so gullible that they would believe the girls.
Firstly Putnams were playing quite a major role, as seen in Act 1 that Mrs Putnam resorted to witchcraft to find out who killed her seven babies when they where not even 1 day old. She was already suspecting that somebody murdered them and not by any illness or disease which then led to her confirming her guesses of who her the witches, one of which is Goody Osburn. Also in act 3, it was stated that Giles Corey that he murder his neighbours for their land accused Mr Putnam by asking Ruth to accuse people for him.
Secondly, Parris was quick to make bad remarks of someone he dislike which when presented in the court, an example would be John Proctor when he tried to help save his wife and friends, Parris pass judgements like “They have come to overthrow the court!” trying to win favour of the judges and at the same time get rid of the people who are against him. He was also scared that he will lose his job as minister and hid the fact that the girls were dancing in the forest so that the members of public will not have a reason to doubt that Parris was sent down from god to guide them.
Thirdly, would be Danforth and Hathorone. Both of them were the judges for this proceeding. They were the best judges in the province and therefore had a lot of pride in them. When the witch trials just started, they convicted many people, but that was not their fault, as any other judge would mistake Abigail as God’s instrument for the fact that they lack evidence. But at Act 3, they were presented with many evidence that certainly showed that Abigail and the girls were fraud, yet they chose to ignore it, tried to hide or ignore for they have a reputation to keep. Once the accusations became crystal clear that they passed the wrong judgements, they refuse to try and correct their actions but rather continue to give improper judgements killing more innocent lives.
These were the people who were secondarily involved in the whole witch trials, and Abigail being the Spark that triggered it all was the primary source of happening.