Abigail offers a great monologue in Act II, scene ii. The problem with this scene is that the author removed it in 1971. So, produced works after that do not always include it.
If you have it, her monologue starts:
Why, you taught me goodness, therefore you are good. It were a fire you walked me through, and all my ignorance was burned away...
A monologue occurs when a player speaks and monopolizes the stage for an extended period. It differs from soliloquy because other folks can be on stage at the same time.
Another example might be in Act I:
Now look you. All of you. We danced. And Tituba conjured Ruth Putnam's dead sisters. And that is all. And mark this. Let either of you breathe a word, or the edge of a word, about the other things, and I will come to you in the black of some terrible night and I will bring you a pointy reckoning that will shudder you. And you know I can do it; I saw Indians smash my dear parents' heads on the pillow next to mine, and I have seen some reddish work done at night, and I can make you wish you had never seen the sun go down!
This is the fullest monologue Abigail gives throughout the piece.