Riker is the sixth offensive lineman to transfer to the Nittany Lions this offseason.
Davis recorded 13 total tackles this season, with his best game coming against Clemson, when he tallied six tackles in Boston College's loss.
Campbell was a key player the Nittany Lions would have loved to have back in 2026.
Henderson picked the Nittany Lions over Michigan State out of high school.
Smith was a four-star recruit in the class of 2024.
Penn State ranked second in the Big Ten conference with 54 receptions of 20 yards or more in 2024, but only 27 came from wide receivers.