Well, as always with this collection of stories, I find that it is actually the main story, or the meta-story, that is most fascinating. This is the story of the pilgrims and their interactions. Clearly the Prologues to the tales that they tell yield particularly rich information about their characters, and this is certainly true of what we learn about the Wife of Bath and the Pardoner. I would say that the three main parallels we can observe in their characters are as follows.
Firstly, both are very open about who they are and their beliefs. Just as the Wife of Bath is overtly feminist and is open about her tactics in marrying rich men and then killing them off with her sexual aggressiveness, so the Pardoner is nothing but open in how he earns his way:
I only preach of avarice and the like,
And in this way induce them to be free
In giving cash--especially to me.
He is open about the way that he lies and deceives people to earn money. Also, another link is the way that money is such an important motive in both of their lives. Both the Wife of Bath and the Pardoner declare that they want an easy life and are willing to do anything to gain it. Finally, both of the tales that they tell are shocking in different ways: the Wife's because of the way that it challenges male patriarchy, and the Pardoner's because of the way it reveals greed to be such a governing factor in our lives as humans. Both tales challenge the accepted view of humans.