If Tom Brady throws for at least one touchdown pass in Super Bowl LIII, Michigan alumni (i.e. Brady) will have the most touchdown passes in Super Bowl history.
Entering Super Bowl LIII, Michigan and Notre Dame are tied for the most Super Bowl touchdown passes (18). The Wolverines and Irish lead 40 college football teams who have at least one touchdown pass, five of whom are in the FCS: Northern Iowa, Delaware, Grambling State, Morehead State, and Youngstown State.
Here's the full list of college football teams whose alumni have at least one Super Bowl touchdown pass (click here for teams with most Super Bowl passing yards):
For college football players who played for multiple schools, their final school was used.