In no particular order...
Macbeth in The Scottish Play
Peter Quince in Midsummer...Dream
Edmund in King Lear
Mistress Quickly in Merry Wives/The Henrys
Pisanio in Cymbeline
Iago in Othello
Friar and the Nurse in Romeo and Juliet
Cassius in Julius Caesar 
Alex in Buyer & Cellar by Jonathan Tollins
Tim in Noises Off by Michael Frayn
The Normal Heart by Larry Kramer
Clybourne Park by Bruce Norris
The Weir by Conor McPherson
Neil in This Bitter Earth by Harrison David Rivers
Amadeus in Amadeus by Peter Shaffer
Christopher Mahon in Playboy of the Western World
In a Word by Lauren Yee
Angels in America by Tony Kushner
Next Fall by Geoffrey Nauffts
Lonely Planet by Steven Dietz
The Father by Strindberg 
Marchbanks in Candida by GB Shaw
A Doll's House by Henrik Ibsen
Orpheus Descending by Tennessee Williams 
the clowns in The 39 Steps by Patrick Barlow
Billy in Carousel 
George in Sunday in the Park with George
The D'ysquith Family in A Gentleman's Guide to Love and Murder
Ensemble in Come From Away
Ensemble in Waitress
Ensemble in Peter and the Starcatcher 
Ensemble in Indecent by Paula Vogel 
Various works by Noel Coward
Various works by Anton Chekhov