There are certainly a wide variety of prejudices exhibited by Harper Lee in To Kill a Mockingbird. Racism is the most obvious, and it is displayed by many different characters--from the hatred of Tom Robinson shown by the Ewells, to the more subtle distinction of black and white seen in the jury's verdict. Many of the children--including Jem and Scout--use the "N" word, though sometimes innocently, to describe Negroes; adults, including the women of the Missionary Circle, are more hateful in their useage of the word.
There is prejudice shown against those with mental instability, particularly Boo Radley; and with those believed to be unstable (Dolphus Raymond). Women receive uneven treatment from many of the citizens, including through Scout's narration. Many of Scout's neighbors, including Miss Rachel and Miss Stephanie, seem to be regarded as odd because of their marital status and love of gossip. The Misses Tutti and Frutti are scorned because of their deafness, place of birth and political orientation (they are Republicans). Children are also looked down upon, particularly by Mr. Avery, who blames Jem and Scout for the unseasonable snowfall. The Cunninghams and Ewells are denigrated because of their heritage and financial shortcomings. Outsiders, such as Miss Caroline, are also looked down upon.