Well if your only talking about a run play from scrimmage, Fred Taylor's 90-yard touchdown run in January 2000 vs. Miami is the longest run play in NFL playoff history! The second longest being Ray Rice's 83-yard touchdown run on the first snap from scrimmage against the New England Patriots
Isaac Redman of Bowie State University set the record for the longest run from scrimmage (99 yards) versus Morgan State University in 2005.
Willie Parker of the Pittsburgh Steelers in Super Bowl XL vs. Seattle.His 75-yard touchdown run is the longest run from line of scrimmage in Super Bowl history, surpassing Marcus Allen's 74-yard run in Super Bowl XVII.Willie Parker's TD was a run. The longest touchdown passwas to wide receiver Mussin Mohammed from QB Jake Delhomme of the Carolina Panthers for 85 yards in 2004.
A 90 yard touchdown pass from Bert Jones to Roger Carr against the Jets in 1975.
Jake Delhomme and Muhsin Muhammad an 85-yard touchdown
In Super Bowl XL, running back Willie Parker of the Pittsburgh Steelers reeled off a 75-yard touchdown run against the Seattle Seahawks.
99 yards ... a play that goes from the offensive team's one yard line all the way for a touchdown.
Mark Malone caught the longest touchdown pass in Steelers history which covered 90 yards. It was thrown by Terry Bradshaw against the Seattle Seahawks on November 8, 1981.