I've tried to come up with a list of football players who have had their number retired in both college AND the NFL. I've never seen a resource that combines both; it's either NFL retired or college by college but not both together. This is what I've got so far.
Piccolo is obvious: #31 Wake and #41 Bears. If Wake ever retires Bill George's number, we'll have two college/NFL as the Bears also retired George's #61. For some inexplicable reason, Walter Payton's Jackson State #34 isn't retired but I can't determine if anyone wears it or has in recent years.
Dick Butkus: #50 Illinois and #51 Bears.
Red Grange: #77 Illinois and Bears.
Jim Brown had his retired by the Browns but his #44 at Syracuse was retired for Brown, Davis, and Floyd Little who wore it (among others) in that order.
Marino's #13 at Pitt and Miami.
Unitas #19 at Louisville and the Colts.
Earl Campbell #20 Texas and #34 Oilers.
Reggie White #92 Tennessee and Eagles and Packers.
Bronco Nagurski #79 Minnesota and Bears.
Doak Walker #37 SMU and Lions.
Barry Sanders #21 Oklahoma State and #20 Lions.
Sammy Baugh #45 TCU and #33 Redskins.
Steve Young #8 BYU and 49ers.
Steve Largent #83 Tulsa and #80 Seahawks.
Marshall Faulk #28 SDSU and Rams.
Piccolo is obvious: #31 Wake and #41 Bears. If Wake ever retires Bill George's number, we'll have two college/NFL as the Bears also retired George's #61. For some inexplicable reason, Walter Payton's Jackson State #34 isn't retired but I can't determine if anyone wears it or has in recent years.
Dick Butkus: #50 Illinois and #51 Bears.
Red Grange: #77 Illinois and Bears.
Jim Brown had his retired by the Browns but his #44 at Syracuse was retired for Brown, Davis, and Floyd Little who wore it (among others) in that order.
Marino's #13 at Pitt and Miami.
Unitas #19 at Louisville and the Colts.
Earl Campbell #20 Texas and #34 Oilers.
Reggie White #92 Tennessee and Eagles and Packers.
Bronco Nagurski #79 Minnesota and Bears.
Doak Walker #37 SMU and Lions.
Barry Sanders #21 Oklahoma State and #20 Lions.
Sammy Baugh #45 TCU and #33 Redskins.
Steve Young #8 BYU and 49ers.
Steve Largent #83 Tulsa and #80 Seahawks.
Marshall Faulk #28 SDSU and Rams.