In "Everyday Use" the greatest symbol is the quilts, which represent intergenerational heritage and connection. there are many other symbols Alice Walker uses, such as names, which for Dee represent freedom versus oppression, and clothes, which symbolically represent the inner qualities of the characters.
One example of allusion in "Everyday Use" is an entertainment allusion to the Johnny Carson show. Allusions draw on common knowledge to make complex statements in an abbreviated manner. Therefore only someone familiar with Johnny Carson's talk show could understand the allusion to "keep up with my quick and witty tongue"; Walker assumes an almost universal acquaintance with Johnny Carson by using this allusion.
One instance of verbal irony is Mrs. Johnson's comment, as the first-person narrator, that while reading aloud Dee "burned" she and Maggie with "a lot of knowledge we didn't necessarily need to know." By this she ironically indicates that Dee, college educated, values knowledge of a higher order and for its own sake (or its own impressive sake), whereas she and Maggie value knowledge that pertains to what they need. It's also ironic to say essentially that (at least some) knowledge isn't worth knowing.