While it would be unfair to categorize each character as either "good" or "bad," one could fairly discuss whether each character had positive or negative intentions throughout the play.
Reverend Parris: He is depicted as a selfish, greedy man who perpetuates the witchcraft hysteria while ignoring the truth in order to solidify his important position in the community. He encourages Deputy Governor Danforth and Judge Hathorne to disregard John Proctor's testimony and arrest him for contempt of court. He also shows no remorse or concern for anyone else's well-being besides his own throughout the play.
Abigail Williams: While one could argue that her actions are a result of growing up in an austere, oppressed society with a selfish uncle, she is portrayed as a malevolent character throughout the play. She publicly accuses innocent people of witchcraft and attempts to get rid of Elizabeth Proctor. She also threatens the other girls and robs her uncle before she flees Salem.
John Proctor: While John makes several questionable decisions that are rather selfish throughout the play, he ultimately reveals his integrity and morally upright character by becoming a martyr at the end of the play. John refuses to sell out his friends and makes the difficult decision to tear up his false confession knowing that he will die.
Deputy Governor Danforth: He is portrayed as a callous, controlling man who dismisses the truth in order to protect his position of authority.
Reverend Hale: While Hale initially supports Salem's court, he experiences an inner change after realizing that it is corrupt. Hale feels extremely guilty for his part in sentencing innocent citizens and quits the court. By the end of the play, Hale tries his best to convince the incarcerated citizens to confess in order to save their lives.
Elizabeth Proctor: While Elizabeth is initially portrayed as a callous, cold wife, she ends up revealing her compassionate nature by supporting her husband's difficult decision towards the end of the play.