Identify the common noun in the following sentence " New York University is the college I attend"

The common noun would be college, because New York University is a proper noun. Attend is a verb and there are no other nouns.

college

Explanation:

In the sentence, there are two nouns: "New York University" and "college." While the former is a proper noun because it names a particular university or institution and begins with a capital letter, "college" is a common noun because it names an institution in a general way, and is not capitalized (Common nouns are not to be capitalized unless they begin a sentence or are part of a title).